Enhancing Hospital Pharmacy Operations Through Lean and Six Sigma Strategies: A Systematic Review

Hospital pharmacies are integral to the healthcare system, and evaluating the factors influencing their efficiency and service standards is imperative. This analysis offers global insights to assist in developing strategies for future enhancements. The objective is to identify the optimal Lean Six Sigma methodologies to improve workflow and quality of hospital pharmacy services. A strategic search, aligned with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, encompassed an extensive range of academic databases, including Scopus, PubMed/Medline, Web of Science, and other sources for relevant studies published from 2009 to 2023. The focus was on management tactics and those examining outcomes, prioritizing publications reflecting pharmacy operations management's state. The quality of the selected articles was assessed, and the results were combined and analyzed. The search yielded 1,447 studies, of which 73 met the inclusion criteria. The systematic review found a low to moderate overall risk of bias. The number of publications rose during the coronavirus disease (COVID-19) outbreak. Among studies, research output in the United States of America represented 26% of the total. Other countries such as Indonesia, Spain, Canada, China, Saudi Arabia, the United Arab Emirates, and the United Kingdom also made significant contributions. Each country accounted for 12%, 8%, 7%, 5%, 5%, 5%, and 5%, respectively. The pharmacy journals led with 26 publications, and healthcare/medical with 14. The quality category came next with 12 articles, while seven journals represented engineering. Studies used empirical and observational methods, focusing on practice quality enhancement. The process control plan had 26 instances, and the define, measure, analyze, improve, and control (DMAIC) was identified 13 times. The sort, set in order, shine, standardize, and sustain (5S) ranked third, totaling seven occurrences. Failure mode and effects analysis (FMEA) and root cause analysis were moderately utilized, with six and four instances, respectively. Poka-Yoke (mistake-proofing measures) and value stream mapping were each counted three times. Quality improvement and workflow optimization dominated managerial strategies in 22 (30.14%) studies each, followed by technology integration in 15 (20.55%). Cost, patient care, and staffing each featured in three (4.11%) studies, while two (2.74%) focused on inventory management. One (1.37%) study each highlighted continuing education, collaboration, and policy changes. Analysis of the 73 studies on Lean and Six Sigma in hospital pharmacy operations showed significant impacts, with 26% of studies reporting decreased medication turnaround time, 15% showing process efficiency improvements, and 11% each for enhanced inventory management and bottleneck/failure mode reduction. Additionally, 9% of studies observed decreased medication errors, 8% noted increased satisfaction and cost savings, 6% identified enhancements in clinical activities, 3% improved prescription accuracy, 2% reduced workflow interruptions, and 1% reported increased knowledge. Also, this study has identified key strategies for service delivery improvement and the importance of quality practices and lean leadership. To the best of the author's knowledge, this research is believed to be the first in-depth analysis of Lean and Six Sigma in the hospital pharmacy domain, spanning 15 years from 2009 to 2023.


Introduction And Background Introduction
Lean Six Sigma (LSS) initiatives have allowed industrial and service organizations to achieve impressive cost savings, productivity increases, and business sustainability [1].The ongoing advancements in technology within the healthcare sector have consistently enhanced processes and procedures by applying LSS tools [2,3].According to Rathi et al. [4], most healthcare LSS studies have focused on management processes, with a noticeable increase in attention from developing nations.Consequently, there has been a shift from focusing solely on preventing and identifying defects and errors to achieving optimization through the digitalization of healthcare and the implementation of "real-time" process control [5].These advancements can be attained by utilizing the most up-to-date applications of LSS methodologies [6].
Jones et al. [7] conveyed that 70% of any change management initiative might fail without proper measurement.LSS offers consistent measurements by standardizing work and continuously evaluating processes, enabling a structured approach to improvement that prioritizes customer or patient satisfaction in the healthcare domain [8].These processes consist of recurring, proactive evaluations and enhancements -commonly referred to as the continuous improvement tools of LSS.Also, it prioritizes and captures issues in daily work.LSS tools track progress, sustain initiatives, and prevent fallbacks, and that is why, essentially, LSS drives productive healthcare, business, and patient-centered solutions.
In the global healthcare landscape, hospital pharmacies are critical nodes within the broader medical system, directly impacting patient care and healthcare delivery [9].The effectiveness of these pharmacies is profoundly influenced by their management strategies, which affect operational efficiency and patient outcomes.As healthcare demands grow and resources become increasingly strained, especially in areas facing economic challenges or healthcare disparities, optimizing pharmacy operations is more critical than ever.
The complexity of managing a hospital pharmacy involves navigating many challenges, from ensuring the safe and timely distribution of medications to effectively managing inventory, staff, and information systems and achieving and maintaining quality accreditations [10,11].In regions like the Gulf and Middle East, these challenges are compounded by rapid population growth, the prevalence of chronic diseases, and unique cultural and regulatory landscapes.The adoption of innovative and strategic management practices in hospital pharmacies can lead to significant improvements in operational efficiency, which in turn can reduce wait times, lower costs, and ultimately lead to better patient outcomes.
Moreover, with the global rise of international standards and the increasing interconnectivity of healthcare systems, understanding and implementing effective management strategies in hospital pharmacies have implications that exceed regional boundaries.

Lean Methodology
The lean methodology originated at Toyota after World War II and focuses on developing a comprehensive manufacturing system to eliminate waste and promptly meet customer demands [12].It strives to optimize the flow of value through various processes and emphasizes respecting individuals [13].Lean defines value as the benefit provided to customers and identifies the main types of waste: excessive work in progress, inefficient processes, and unused employee skills.The successful implementation of lean necessitates active employee engagement and the establishment of a culture of continuous improvement across the entire organization [14].A lean culture includes ongoing training and development, encouraging employee participation, and maintaining consistent standards [15].This approach allows adaptability and responsiveness in today's fast-paced environment and provides a straightforward yet efficient problemsolving system [16].

Six Sigma Methodology
Six Sigma is a methodology for improving quality formally, focusing on reducing defects in a process.The term "Six Sigma" indicates that these processes aim to produce a product with no more than 3.4 defects per million cycles, demonstrating high accuracy.Six Sigma employs a structured approach, utilizing data and statistical analysis to evaluate and enhance a company's operational performance.A key component of Six Sigma is its define, measure, analyze, improve, and control (DMAIC) process, an abbreviation for Define-Measure-Analyze-Improve-Control.Initially developed by Motorola in the 1980s, this business strategy applies not only to operational and manufacturing processes but also to transactional and administrative processes.Thus, Six Sigma techniques can improve the quality of business processes, including healthcare operations [17].The DMAIC process offers a systematic and organized approach to problem-solving, ensuring that issues are addressed and prevented from recurring.It promotes data-driven decision-making and encourages collaboration among team members, ultimately leading to sustainable and practical solutions [12].

Combining Lean and Six Sigma Tools and Strategies
LSS methodologies have been used to reduce or eliminate waste in production processes, clients' waiting time, and product defects.However, little is known about how Lean and Six Sigma can be effectively combined and applied in healthcare management, especially in hospital pharmacy [18].The combination of Lean and Six Sigma methodologies in healthcare operations, particularly within hospital pharmacies, offers a synergistic approach that optimizes both the efficiency and quality of patient care.The lean methodology focuses on eliminating waste and enhancing workflow processes, while Six Sigma aims to minimize variability and defects through rigorous data analysis.When these methodologies merge, they create a robust framework for achieving operational excellence.This approach ensures that process improvements are directly aligned with the patient's needs, guaranteeing that each step adds value and meets the highest quality standards.By adopting this integrated approach, operations are streamlined, and a culture of continuous improvement is fostered.The goal becomes solving problems as they arise and proactively designing systems that minimize errors.Thus, the combination of Lean and Six Sigma strategies exceeds simply enhancing operations -it strives to transform the culture of hospital pharmacy services, making them as effective, reliable, and patient-centric as possible.

Objective of the Review
This systematic review aimed to thoroughly examine the global practices of Lean and Six Sigma methodologies in hospital pharmacies to identify the most effective strategies in operations management [19].The essence is categorizing and evaluating efficient methods and instruments for pharmacy operations management incorporating LSS techniques [20][21][22].By integrating various approaches, this review aimed to gather a comprehensive source that covers various methodologies and tools used worldwide, focusing on improving pharmacy services to align with complex healthcare processes [23][24][25].
Considering the healthcare nature of zero tolerance for medication errors, as Khaidir et al. [26] highlighted, the main objective was to provide pharmacies with a definitive guide to improving their operations and enhancing the quality of patient care through the strategic application of LSS techniques, serving as a crucial benchmark and roadmap for optimal operational performance.

Research Question
What LSS tools, strategies, and unique operation management approaches were used in hospital pharmacies worldwide to enhance work efficiency and patient service quality?Moreover, what are the main takeaways and the practical consequences of implementing LSS from a managerial perspective?
The review examined the impact of integrating Lean and Six Sigma strategies as operations management tools on hospital pharmacy administration.The question was straightforward, precise, and easily comprehensible.

Search Strategy
The search strategy for this systematic review was carefully developed and executed under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [27].The research commenced by identifying three primary concepts central to the question: Hospital Pharmacy, Lean Methodologies, and Six Sigma.For Hospital Pharmacy, the search focused on "Hospital Pharmacy*" OR "Pharmacy*" OR "Pharmacy Practice in Hospitals" OR "Hospital-based Pharmacy," aiming to capture the diverse aspects of pharmacy practice within the hospital setting.The second concept, Lean Methodologies, was explored using terms like "Lean principle*" OR "Lean Six Sigma" OR "Lean Process*" OR "Lean think*" OR "Lean Method*" OR "Toyota Lean System*" OR "Lean Practice*" OR "5S Lean" OR "Lean Healthcare" OR "Lean Implementation in Pharmacy", to gather insights into the application of lean principles in improving efficiency and effectiveness in healthcare, specifically in pharmacy operations.Finally, for Six Sigma, the search included "Six Sigma" OR "Six Sigma in Healthcare" OR "DMAIC," focusing on this methodology's specific application in healthcare, particularly in enhancing quality and operational excellence in hospital pharmacies.This comprehensive approach was designed to ensure an extensive understanding of how these methodologies contribute to hospital pharmacy practice.Boolean operators (AND, OR, NOT) combined keywords into a comprehensive search series [28].Then, they were tailored to the syntax and requirements of multiple databases.The initial search was conducted in one database (Scopus) to assess the relevancy and range of the results, leading to further refinement of the search terms.The process ensured the capture of the most relevant and comprehensive literature available.The search strategy for each database is demonstrated in Table 1.

TABLE 1: Database complete search strategy
This thorough and systematic approach was created to fully encompass worldwide perspectives on the strategies used in managing the quality of pharmacy operations, which played a significant role in promoting excellence and improving results in hospital pharmacies.

Information Sources
The databases for this systematic review included Scopus, PubMed/MEDLINE, and Web of Science (WoS).To ensure a thorough search, an additional search engine, Google Scholar, was employed.

Inclusion and Exclusion Criteria
For inclusion, the study considered peer-reviewed empirical research articles that provided data on operations management strategies in hospital pharmacies.Distinct from direct clinical treatment results, these studies needed to investigate and provide precise data on management strategies in hospital pharmacy settings, including waste elimination, technological integrations, process and workflow optimizations, staffing models, quality and medication safety improvement initiatives, and policy changes.
They were required to report on outcomes related to operational efficiency metrics such as medication error rates, inventory turnover, prescription processing time, medication utilization, and cost reduction.Furthermore, they were required to furnish information about measurable indicators of patient service excellence, including the duration patients waited, the ease of accessing services, surveys assessing patient satisfaction, and the effectiveness of communication between staff and patients.The geographical scope was global with no restrictions, and only studies were published within the last 15 years, from January 2009 to December 2023.Moreover, only English-language articles were considered.
Exclusion criteria included non-empirical studies such as editorials, opinion pieces, technical reports, and commentaries.Studies that did not address hospital pharmacy activities, lean methodologies, or Six Sigma applications in pharmacy healthcare settings were also excluded.Furthermore, non-peer-reviewed sources, preprints, and articles in the non-English language were not considered.

Review, Selection Process, Data Extraction and Synthesis
The selection process for this review followed the structured PRISMA flow diagram, beginning with collecting records from various databases and sources.EndNote 20, a reference management tool, was utilized for the organization and evaluation of titles and abstracts, and it also aided in detecting duplicate entries.Duplicates were first removed, followed by a careful screening by the author for titles to include articles with Pharmacy AND Lean OR Six Sigma.Two independent field expert reviewers evaluated abstracts for the included articles to determine the relevance of each article.Disagreements were resolved through discussion.The potentially relevant articles then underwent a full-text review by the author for final inclusion, with clear documentation provided for any excluded articles.
In parallel, data from the included studies were carefully extracted using an Excel sheet, capturing critical details such as the study design, specific management strategies employed, and outcomes for pharmacy operations and patient care.The data were then narratively synthesized, summarizing the main findings and identifying trends regarding operations management tools and strategies across hospital pharmacies worldwide.This approach ensured a transparent and thorough analysis, offering a detailed understanding of the various management strategies and their implications within the global context of hospital pharmacies.

Quality Assessment
The research articles included in the study were analyzed using the risk of bias in non-randomized studies of interventions (Robins-I) and risk of bias 2 (ROB 2) tools, respectively [29][30][31].Cohort and case-control studies were evaluated with the Newcastle-Ottawa Scale, which assesses the selection of study groups, the comparability of the groups, and the ascertainment of the outcome or exposure [32].These tailored tools and rigorous assessment ensured a systematic and standardized evaluation of the risk of bias and overall quality, which is crucial for accurately interpreting the systematic review results and including reliable and highquality articles, strengthening research findings.

Data Analysis
The gathered data were compiled in a summary table, and subsequently, manual content analysis was employed for the classification, mapping, and graphics for the findings using Microsoft Excel 2021 [33].

Results
A total of 1,447 files were identified from searching databases, and following the full screening activity, a total of 73 records were eligible to be included in the review.The record selection process is outlined in the PRISMA flowchart provided in Figure 1.

Overview of Included Studies
This summary provides a full description of each study included in the systematic review, detailing important aspects such as the study's reference, publication year, geographical setting, study design, data collection methods, objectives, and hospital size.The comprehensive overview presented the research and management strategies, interventions conducted, metrics used, measured indicators, outcomes evaluated, and results for each study.In addition, the author suggested measures and conclusions to enhance the breadth and depth of the research, establishing a solid comprehension of the context and specific contributions of all the studies included.

Risk of Bias in the Included Studies
The overall biases resulting from confounding, participant selection, intervention classification, deviation from intended interventions, outcome measurement, and reported results are considered to have a low to moderate risk, with a few studies lacking sufficient information to determine the risk level.Missing data are notable for having a moderate risk.This underscores the need for careful consideration when interpreting the systematic review's findings [29,30].The evaluation of bias risk in the included studies is presented in the provided bar chart in Figure 2.

FIGURE 2: Publication quality risk-of-bias assessment
Risk-of-bias VISualization (robvis) used to create risk-of-bias plot [30] 2024 Initially, only two studies were published in 2009; However, the volume of papers showed an irregular yet predominantly upward trend throughout the years.Notably, there was a significant surge in 2020, 2021, and 2022, with the number of studies peaking at 9, 9, and 8, respectively.This increase in published studies during these years could indicate a heightened research activity in response to the global COVID-19 pandemic.The increased focus on LSS methodologies is likely a result of the urgent necessity to reduce medication wastage and optimize healthcare processes during that critical period.The above underscored the crucial role of such studies in adapting to the challenges presented by the pandemic, which may have acted as a catalyst for research and innovation in this field worldwide [106].Figure 3

FIGURE 5: Percentage of global geographical distribution of pharmacy Lean Six Sigma studies
Map generated using the "Insert Map Chart" option in Microsoft Excel 2021 [33] Darker shades on the map in Figure 4 indicate countries with a higher frequency of studies.Figure 5 reveals that the United States of America (USA), with 26% of studies, was the predominant contributor during the study timeframe.Alongside the USA, Indonesia (12%), Spain (8%), Canada (7%), China, Saudi Arabia, the United Arab Emirates (UAE), and the United Kingdom (UK) were also projecting in terms of research output with (5%) each.The geographical spread of the studies across different continents highlighted the global interest and the diverse investment in the research areas covered.The research was not confined to any particular region but a worldwide effort with active involvement from multiple countries.Representing countries from continents and areas such as North America, Asia, the Middle East, Europe, and Australia painted the extensive range and critical importance of the subjects investigated in these studies.

Journal Fields
The Pareto chart in Figure 6 exhibits the distribution of published research in different disciplines of distinct journals.It clearly pointed out a notable dominance of 26 journals in the pharmacy sector.The healthcare/medical category ranked second with 14 publications, closely followed by the quality category with 12 articles.Engineering journals were represented with seven articles.This distribution underscored the focus of this review, stressing advancing knowledge and practical application in pharmacy, healthcare, and quality.

Designs of the Included Studies
After a comprehensive analysis of 73 studies conducted in the hospital pharmacy within the healthcare industry, it became apparent that there was a notable emphasis on utilizing practical and observational approaches.Observational studies, in particular, made up a significant portion of the research designs identified.These studies encompassed a wide range of topics, from analyzing the systems within inpatient medication dispensing units to examining the risk management practices in hospital pharmacies.This demonstrated a focus on current practices and their outcomes.Another standard research design was the retrospective descriptive study, which provided valuable insights into past performance and trends over an extended 19-month period [36].Quality improvement initiatives were also well-represented in the research landscape.These initiatives often utilized the Six Sigma approach and failure mode and effects analysis (FMEA).They frequently involved staff surveys and interventions to improve operational efficiency and patient care.Many studies also employed lean management techniques, indicating a noticeable shift within the healthcare industry toward more streamlined and patient-centric service delivery.
Additionally, case studies played a vital role in the research conducted, as they provided a detailed examination of specific interventions or changes within a single entity, such as a hospital unit or outpatient pharmacy [14].This approach was crucial for understanding the practical application of theoretical models.While less common, experimental designs also contributed to the empirical evidence base, particularly in process improvement and technology integration.These studies varied in duration, some lasting only a few months while others spanned several years.This highlighted the diverse scopes and scales of research within healthcare improvement initiatives.The methodologies utilized across these studies demonstrated a strong and dynamic approach to understanding and improving healthcare processes, with a clear preference for observational and quality improvement research in real-world clinical settings.

Visualization of Relevant Key Terms
A word cloud was generated by the author (Figure 7) using a web-based word cloud generator [107] to showcase and highlight the primary themes and methodologies used in the selected articles.This visualization, emphasized the terms hospital, pharmacy, lean, six, and Sigma as the most frequently mentioned terms, indicating that the review focused on LSS practices in the field.The abbreviation LSS, which stands for LSS, was also prominently featured, further highlighting its importance.Moreover, the concepts of improvement, process, management, methodology, and efficiency were frequently referenced, demonstrating the continuous venture of excellence in operational practices in hospital pharmacies.The terms FMEA and define, measure, analyze, improve, control (DMAIC) also indicated a systematic and analytical approach to quality and risk management.While less common, terms like clinical, quality, risk, performance, and healthcare were used in conjunction with other terms to provide a comprehensive overview of the strategic priorities in hospital pharmacy research during the reviewed period.

FIGURE 7: Main keywords visualized as a word cloud
The word cloud visualization was obtained from TagCrowd: a web-based word cloud generator [107] Numbers next to each word show the keyword count frequency in the selected articles Credit: Dr. Mohammed Sallam

LSS Tools and Techniques Used in the Context of Hospital Pharmacy
The Pareto chart in Figure 8 displays the frequency of using different LSS tools and techniques in hospital pharmacy settings.This chart offers considerable knowledge and a detailed guide for industry professionals, enabling them to accurately recognize the most frequently used methods and approaches.By examining the distribution of occurrences illustrated in this visual representation, professionals working in hospital pharmacies can make well-informed choices, prioritize their actions, and effectively allocate resources to achieve the best results in enhancing quality and streamlining processes.The process control plan was the most widely utilized tool, with a count of 26, indicating its crucial role in managing and controlling processes.Following closely was DMAIC, with a count of 13, showing its significant application in improving processes within the sector.The 5S method ranked third in popularity, with a count of seven, highlighting its implementation for organizing and improving efficiency [108].Tools like FMEA and RCA, which involve risk assessment and problem-solving, had moderate usage with counts of six and four, respectively.Poka-Yoke (mistake-proofing) and value stream mapping, each with a count of three, were also notable as they are crucial in reducing errors and optimizing workflows.Other LSS tools such as brainstorming, Gemba walks, Kaizen, and PDCA had lower frequencies, ranging between one and two counts, suggesting that they are utilized in more targeted situations or as complements to frequently used techniques.Suppliers, inputs, processes, outputs, and customers, Six Sigma as a standalone tool, and time and motion study each have a count of one, indicating that they have niche or particular use cases in the presented context.The cumulative percentage line graph showed a steady increase towards 100%, demonstrating the widespread adoption of these LSS tools in hospital pharmacies.This upward trend reflected the comprehensive range of methodologies used for optimizing processes, improving quality, and enhancing efficiency in healthcare.The data highlighted the diverse array of LSS terms and methodologies implemented in practice, with some playing a more central role in operations than others [109].

Various Management Strategies
The most commonly reported strategies were quality improvement initiatives and workflow optimizations, illustrated with 22 (30.14%)studies each.Close behind were technological integrations, with 15 (20.55%) studies.On the other hand, cost management, patient-centered care, and staffing models had three (4.11%)studies each.Inventory management enhancements showed two (2.74%) studies.Finally, continuing education, interdisciplinary collaboration, and policy changes were represented by one (1.37%)study for each.
Figure 9 presents a doughnut graph that provides objective quantitative data on the frequency of different management strategies utilized.This graph highlighted an apparent inclination toward strategies primarily concentrating on quality improvement, workflow optimization, and technology integration.

FIGURE 9: Doughnut chart for different management strategies
Outcome Measured/Analysis The compilation of studies encompassed a variety of outcomes, highlighting significant advancements and areas of focus in the pharmacy operations management field.Many studies prioritized reducing medication and dispensing errors through strategies like analyzing failure modes in medication management and implementing robust systems, aligning to improve patient safety and care quality.A central theme was the enhancement of workflow efficiencies by reducing disruptions from routine inquiries and improving the speed and dependability of medication dispensing, especially in emergencies.Regarding inventory management, several studies focused on optimizing stock utilization and turnover, notably reducing unnecessary drug usage.The patient-centric approach explored satisfaction levels, wait times, and clinical intervention effectiveness.Operational and financial efficiency examined initiatives' impact on hospitals' financial performance, balancing cost-effectiveness and quality care.Additional research is imperative to analyze the effects of various indicators on hospitals' financial performance.The aim is to attain a balanced state of optimal cost efficiency and exceptional quality of patient care [110].Staff efficiency and satisfaction involved evaluating processes to enhance working conditions, thereby improving pharmacy services' operational aspects and contributing to higher morale.Quality and safety in medication management were at the forefront of the studies that assessed pharmacy systems' effectiveness in mistake reduction and safety practices.Other studies measured advancing knowledge and skills, especially in lean management principles, reflecting the evolving nature of pharmacy practice.Though not quantified here, interdisciplinary collaboration and sustainable practices in pharmacy operations appeared as themes emphasizing hospital efficiency, patient care pathways, responsible waste management, and environmentally sustainable methods.These studies illustrated a changing landscape in hospital pharmacy management, focusing on safety, efficiency, patient-centered care, and continuous improvement.

Discussion
The systematic review, consisting of 73 studies that examined the implementation of Lean and Six Sigma methodologies in hospital pharmacy operations, yielded 11 valuable insights.Analysis of the results offered a comprehensive understanding of how these methodologies impact various aspects of pharmacy operations.Notably, 26% of the studies highlighted a significant decrease in medication turnaround time.This finding holds great importance given the time-sensitive nature of medication delivery in healthcare settings.The effectiveness of Lean and Six Sigma methodologies in streamlining pharmacy operations was clearly evident and suggested improved operational efficiency in delivering patient care.Process efficiency improvements were a prominent focus in 15% of the studies.These improvements were critical in optimizing pharmacy workflow, resulting in more efficient operations.The emphasis on efficiency indicated that these methodologies have the ability to refine processes for enhanced performance.
Further, 11% of the research emphasized identifying bottlenecks in processes and failure modes and minimizing non-value-added activities.This particular theme closely aligns with LSS's fundamental principles, which greatly emphasize reducing waste and optimizing processes.Another group of studies, also at 11%, focused on enhancing inventory management.This aspect holds considerable significance in hospital pharmacies, as efficient management of pharmaceutical stocks can significantly impact costs and patient care.The studies found that reducing medication errors, which accounted for 9% of the research, was evidence of the improved accuracy and safety inherent in the streamlined processes.This finding is significant in healthcare settings, where errors can have severe and, at times, fatal consequences.
In addition, 8% of the studies found that implementing these methodologies increased satisfaction rates among staff and patients.This suggests that applying LSS tools not only improved operations but also positively impacted overall satisfaction.Another 8% of studies showed reduced medication expenditure, demonstrating the financial benefits of effectively managing resources through these tools.Approximately 6% of the studies indicated improvements in clinical pharmacy activities, showing a shift towards a patientcentered approach and optimized clinical outcomes.Additionally, 3% of the studies highlighted improvements in prescription checking and intervention success rates, highlighting the role of these methodologies in enhancing the quality of pharmacy services.A decrease in workflow interruptions was observed in 2% of the studies, indicating a more consistent and uninterrupted pharmacy service.Lastly, 1% of the studies reported increased knowledge, which is crucial for continuous improvement and adaptation in dynamic healthcare environments.
Figure 10 illustrates the percentages of theme occurrence in the review studies.

FIGURE 10: Percentage distribution of theme occurrence in the research
Reduction in medication turnaround time (26%), improvements in process efficiency (15%), identification of process bottlenecks, failure modes, and reduction of non-value-added activities (11%), improvements in inventory management (11%), reduction in medication errors (9%), increase in satisfaction rate (8%), reduction in medication expenditure (8%), improvements in clinical pharmacy activities (6%), improvements in prescription checking and intervention success rates (3%), reduction in workflow interruptions (2%), increase in knowledge (1%) The structured review and analysis brought to light a piece of persuasive and concrete objective evidence that implementing Lean and Six Sigma methodologies yielded multiple enhancements in hospital pharmacy operations.These improvements encompassed increased efficiency and precision, financial management, and enhanced patient care, highlighting LSS methodologies' extensive and varied influence on pharmacy operations.
This review focused on the range of tools and management approaches employed in hospital pharmacies within the operations management scope under Lean and Six Sigma frameworks [111].The pharmacy operational performance across the studies strongly correlates with implementing lean healthcare practices [15].Most of LSS's tools rely heavily on data to comprehend issues [112].Data is a vital requirement to commence any process enhancement.The incorporation of intelligent technologies enables clients, suppliers, and employees to participate actively in real-time data collection.Implementing LSS in healthcare domains emphasizes the necessity to establish a standardized framework for its prosperous execution across the entire sector [113].
One such tool is the voice of the customer (VOC), which aids in understanding customer needs.Some of the included studies focused on how qualitative data gathered from the VOC was translated into innovations and enhancements in pharmacy services.Additionally, key performance indicators (KPIs) were examined to evaluate the effectiveness of pharmacy processes and measure progress.Examples of pharmacy KPIs include the number of prescriptions processed, the number of errors detected before reaching the patient, the cost per prescription, and wait times.The third tool, critical-to-quality (CTQ), was explored concerning creating and optimizing processes within the pharmacy.The CTQ tree has been introduced within studies, outlining different significance levels.Last, some articles introduced critical success factors (CSFs) as broader goals that pharmacy teams strived for.It emphasized aligning daily activities with vital strategic areas [114].

Reduction in Medication Turnaround Time and Impact on Patient Experience
Reducing medication turnaround time has been crucial in improving hospital pharmacy services.The review has presented compelling evidence, with various studies documenting significant reductions in turnaround time ranging from 9% to 93%.These notable decreases illustrated a noteworthy improvement in how medications were dispensed, highlighting a broader commitment to enhancing operational efficiency and patient satisfaction.The aggregated data demonstrated a concerted effort within the field to optimize pharmacy workflows, resulting in reduced wait times for patients and improved timely administration of medications.The recurring presence of this theme in multiple studies reaffirms the critical nature of turnaround time in healthcare provision.The progress made in this area is supported by a substantial number of studies, reflecting a collective effort toward more efficient pharmacy practices [39,41,42 48 51,53-55,62,67,69,71,84,87-91,93,97,100,101,103].Reduction in patient waiting times is an essential goal for healthcare facilities to enhance the overall patient experience.By adopting efficient strategies, pharmacy healthcare providers have effectively reduced waiting times in both outpatient and inpatient settings.This reduction significantly benefited patients, ensuring their valuable time was not wasted, and their healthcare needs were promptly met.

Improvements in Process Efficiency
A central theme from the comprehensive review was the significant improvement in operational efficiency within hospital pharmacies.Several studies [60,61,64,74,86,95] provided quantitative evidence of this enhancement, showing notable efficiency increases ranging from 7% to 88%.These advancements signify a shift in focus toward optimizing pharmacy operations by efficiently utilizing resources and streamlining processes for better productivity.The absence of specific percentages in other studies [45,63,65,66,70,73,102] does not undermine the importance of their contributions to this theme.These studies highlighted the continuous efforts to refine pharmacy workflows, minimize redundancy, and improve service delivery.The results of these improvements were evident in the substantial efficiency gains, showcasing the success of different strategies implemented in various settings.
This prevalent theme emphasizes the ongoing commitment in the field to evolve and adapt to the complex demands of healthcare.By embracing innovative approaches and continuous improvement methodologies, hospital pharmacies can significantly enhance the quality of their services, ultimately benefiting patient care.

Identification of Process Bottlenecks, Failure Modes, and Reduction of Non-Value-Added Activities
The systematic review highlighted another central theme in hospital pharmacy practice.Various studies [47,74,82,85,86,94,98] offered quantitative evidence for this trend, showcasing improvements in efficiency metrics ranging from 7% to 74% by reducing non-value-added activities.These numbers illustrate a substantial advancement in pharmacy operations, emphasizing a deliberate effort to eliminate inefficiencies and optimize workflow.Even in studies where specific percentages were not provided [35,68,83], the recurrence of this theme highlights its significance in today's healthcare landscape.These studies collectively indicated an industry-wide initiative to refine processes, a necessary step for the sustainable provision of healthcare services.Notably, one study [94] reported a 65% reduction in the mean risk priority number, demonstrating the depth of this endeavor.This reduction significantly improved identifying and addressing potential failure points in pharmacy operations, ultimately enhancing patient safety standards.This process involved comprehensive assessments of medication processes, identifying potential areas of improvement, and implementing robust strategies to mitigate errors and enhance overall medication management standards.
These insights portray a proactive approach to continuous process improvement.By identifying and resolving bottlenecks, failure modes, and non-value-added activities, hospital pharmacies are improving their operational efficiency and making notable contributions to the broader goals of healthcare quality and patient safety.

Improvements in Inventory and Supply Chain Management
The systematic review has revealed that improving inventory management within hospital pharmacies has been a significant area of focus.Studies that specifically mentioned quantitative enhancements [52,58,97,104] demonstrated notable progress, with efficiency gains ranging from 20% to 76%.These improvements signify a considerable shift toward more precise and effective pharmaceutical stock management, an essential element of pharmacy operations.Even in studies that did not provide specific percentages [37][38][39]43,59,81], the recurring emphasis on improvements in inventory management still provides valuable insights.It suggests a widespread recognition of the necessity for and implementation of better inventory control measures.These measures likely include technological advancements for tracking and forecasting, optimized stock rotation, and strategies to reduce waste effectively.The study that showed a 76% improvement [97] demonstrates how inventory management practices have evolved, significantly reducing inefficiencies and excessive stock.
On the other hand, the study that revealed a 20% improvement [104] suggests that even smaller advancements in inventory management can considerably impact a pharmacy's overall effectiveness.These findings highlight a progressive movement toward enhancing inventory practices in hospital pharmacies.By improving inventory management, these institutions are ensuring the availability of essential medications while simultaneously reducing waste and overall healthcare expenses.The focus on this aspect demonstrates a dedication to financial accountability and the delivery of excellent patient care.

Reduction in Medication Errors
Identified in the systematic review was a crucial theme concerning the significant decrease in medication errors found in hospital pharmacies, a key factor contributing to patient safety.Several studies [42,[48][49][50][76][77][78]104] have reported remarkable reductions in medication error rates, ranging from 42% to 91%.These statistics highlight a fundamental shift toward safer pharmacy practices and improved medication handling and dispensing vigilance.For instance, one study [77] demonstrated a 91% reduction in errors, showcasing the potential for substantial improvements through targeted interventions and system-wide changes.
Similarly, another study [104] showed an impressive 83% reduction, emphasizing the effectiveness of rigorous quality control and error prevention strategies.These studies consistently align with the global healthcare objective of minimizing patient harm by focusing on reducing medication errors.The methods to achieve these reductions likely involve advanced technology, staff training, process re-engineering, and enhanced quality assurance measures.These findings illustrate a dedicated effort within the hospital pharmacy field to tackle the critical issue of medication errors.This progress reflects advancements in technology and procedures and a more substantial commitment to providing patient-centered care and ensuring safety.

Increase in Satisfaction Rate
The systematic review underscored a significant finding: a noticeable improvement in satisfaction rates in hospital and pharmacy settings.This trend, which indicates higher satisfaction levels among patients and staff, can be observed in several studies [13,42,51,55,61,92], with increases ranging from 6% to 82%.These improvements substantially impact how pharmacy services are perceived in terms of quality and effectiveness.In particular, one study [55] reported a remarkable 82% increase in patient satisfaction, demonstrating how efforts to improve medication turnaround times, enhance communication, and implement patient-centric care approaches can significantly elevate satisfaction levels.Even when specific percentages were not provided [44], the focus on increased satisfaction rates shows how hospital pharmacies increasingly prioritize service quality and user experience.Another study found a 69% increase in satisfaction [51], further illustrating the successful adoption of strategies to enhance patient and staff satisfaction.These collective findings demonstrate that hospitals are placing importance on the technical aspects of pharmacy services and the subjective experiences of those who interact with these services.By doing so, hospitals are meeting and often surpassing their patients' and staff's expectations and needs, leading to a more positive healthcare environment.

Improvements in Financial Performance and Reduction in Medication Expenditure (Cost)
The systematic review has revealed a crucial finding concerning the practices of hospital pharmacies: they have been able to lower their medication costs and associated expenses significantly.This finding is of great importance for economic efficiency and healthcare sustainability.The studies [36,39,64,75,80,105] showed reductions in costs that range from 24% to an extraordinary 179%.For example, one study [64] reported a decrease of 179%, which is an exceptional improvement in cost efficiency.This improvement may have been achieved by implementing optimized procurement strategies, better inventory management, and waste reduction measures.Another study [75] found a reduction of 90%, which demonstrates the potential for significant savings in the pharmaceutical field.Even when specific percentages were not mentioned in certain studies [44], the consistent focus on reducing medication costs indicates that this is a priority for the entire industry.
Furthermore, the study [36] reported a reduction of 82%, further emphasizing the trend of implementing cost-effective measures without compromising the quality of care.These findings illustrate the targeted efforts made by hospital pharmacies to decrease medication-related expenses.Such efforts are crucial for the financial sustainability of healthcare institutions and can help make healthcare more accessible by relieving the financial burden on patients and the healthcare system.

Improvements in Clinical Pharmacy Activities and Service Outcomes
The evaluation showcased a noteworthy enhancement in clinical pharmacy operations, emphasizing clinical pharmacists' evolving role and impact in healthcare environments.Prominent progress can be observed in studies [56,57,88,96], which demonstrate significant improvements, ranging from a 50% increase in medication reconciliation to a remarkable 400% increase in ward areas with clinical coverage.Eliminating high-alert medication errors by 100% [57] exemplifies the crucial role played by clinical pharmacists in promoting patient safety and care.This reduction signifies a near-elimination of critical mistakes, highlighting the effectiveness of targeted interventions and increased attentiveness in pharmacy practice.Additionally, the 92% rise in medication reconciliation [88] and the 400% increase in ward areas with clinical coverage [96] indicate a substantial expansion in the range and impact of clinical pharmacy services.These enhancements are likely a result of closer integration between clinical pharmacists and patient care teams, thereby elevating the overall quality of healthcare provision.Even in studies without specific percentages available [99], the recurring emphasis on improvements in clinical pharmacy underscores the significance of joining the power of Lean and Six Sigma methodologies in advancing patient care.These findings suggest that hospital pharmacies are increasingly prioritizing clinical activities, indicating a shift toward a more patient-oriented approach.This shift is pivotal for enhancing patient outcomes, ensuring medication safety, and contributing to the overall effectiveness of healthcare systems.

Improvements in Prescription Checking and Intervention Success Rates
The systematic review has highlighted a critical aspect of hospital pharmacy practice: the notable improvements in prescription verification and intervention success rates.This topic is of utmost importance in ensuring the accuracy of medications and the safety of patients, as evidenced in studies [72,79], where documented improvements range from 25% to 100%.The outstanding 100% improvement reported in one study [79] is remarkable, signifying a scenario where prescription verification and interventions have reached optimal effectiveness.This level of improvement suggests that stringent standards and protocols have been successfully implemented, significantly reducing the risk of medication errors.In another study, a substantial 25% improvement in prescription verification [72] demonstrates progress in enhancing the reliability and precision of medication dispensing processes.This improvement can likely be attributed to a combination of factors, including the adoption of advanced technological systems, improved staff training, and more effective communication within the healthcare team.Even in studies where specific percentages were not provided [40], the inclusion of this topic indicates its significance in the broader context of enhancing pharmacy services.These findings underscore a growing emphasis on accuracy and excellence in pharmacy.By prioritizing improvements in prescription verification and intervention success rates, hospital pharmacies are directly contributing to enhanced patient safety and the overall quality of healthcare delivery.

Reduction in Workflow Interruptions
The systematic review emphasized the significance of reducing workflow interruptions in hospital pharmacy settings, a crucial factor in maintaining efficiency and ensuring continuous patient care.The research [34,71] demonstrated substantial decreases in workflow interruptions, with 60% and 75% reductions, respectively.A 60% decrease in workflow interruptions [34] indicates a noteworthy enhancement in the smooth functioning of pharmacy services.This decrease could be attributed to implementing streamlined procedures, adopting technological solutions for better workflow management, or changing staff communication and task assignment strategies.Particularly remarkable is the 75% reduction [71], which strongly emphasizes reducing distractions and interruptions that can hinder the pharmacy's efficiency.This significant decrease suggests a thorough reevaluation and redesign of workflow processes, potentially incorporating elements such as task automation, improved space utilization, or enhanced coordination between departments.These findings collectively demonstrate a dedicated effort to refine pharmacy operations, underscoring the critical role of uninterrupted workflow in maintaining high standards of pharmacy service.By minimizing disruptions, these pharmacies enhance their operational efficiency and significantly contribute to improved patient outcomes and overall healthcare quality.

Increase in Knowledge
The analysis incorporated a subject centered on the progress of understanding, specifically within the hospital pharmacy setting.As exemplified in the study [46], this subject demonstrates an 18% growth in understanding, highlighting the significance of ongoing learning and skill development in pharmacy practice.The 18% increase in understanding indicates a dedication to professional growth and education in the pharmacy industry.This improvement is likely a consequence of targeted training programs, educational workshops, or initiatives designed to keep pharmacy personnel updated with the most recent industry standards, medication information, and best practices.Such an emphasis on expanding understanding is crucial for ensuring that pharmacists and pharmacy technicians are adequately equipped to handle the complexities of modern healthcare.It emphasizes the worth placed on education to enhance service quality, improve patient safety, and keep up with the evolving demands of the healthcare sector.This focus on knowledge enlargement benefits the individuals involved and has a broader impact on the efficiency and effectiveness of pharmacy services as a whole.The drive to consistently enhance knowledge within the pharmacy sector demonstrates a forward-thinking approach, aimed at fostering excellence and innovation in healthcare.

Quality Improvement Initiatives
Six Sigma has been extensively utilized within the healthcare industry as an effective quality management system [115].Quality improvement initiatives in hospital pharmacy aimed to enhance patient safety, optimize medication use, and improve healthcare outcomes.These initiatives streamlined processes, reduced errors, and ensured high-quality care.Evidence-based practices improved efficiency and effectiveness, fostering excellence and interprofessional collaboration.Effective communication and collaboration among healthcare professionals were vital.Tools like LSS and root cause analysis (RCA) identified causes of errors and developed strategies.Standardized operating procedures, technology solutions, and ongoing education improved safety and efficiency.Quality improvement initiatives also positively impacted financial performance, reducing errors and hospital stays, and improving satisfaction.

Competitive Advantage, Value of Service, and Safety Improvements
Operational excellence is crucial for any business entity to endure and thrive in the international marketplace.Numerous companies have implemented various continuous improvement ideologies to address this matter, including lean manufacturing, Six Sigma, total quality management, agile manufacturing, and more.Both lean manufacturing and Six Sigma have demonstrated exceptional outcomes [116].Additionally, this review emphasized the significance of implementing lean practices and enhancing quality improvement in hospital pharmacy.These measures aimed to boost service delivery while also reducing costs associated with services, transportation, and the availability of affordable medication supplies.Ultimately, these efforts sought to increase patient satisfaction and gain a competitive advantage [106].

Staff Productivity and Motivation
Cleaner and more organized workspaces contributed to improved employee motivation and collaboration and fostered productivity and efficiency [117,118].A tidy workspace helps employees stay focused, reduces distractions, and minimizes the time spent searching for tools and materials [59].Additionally, an organized workspace promotes better time management and task prioritization, allowing employees to complete their tasks more effectively [82].
The shift in pharmacist activities from non-value-added to value-added activities significantly impacted productivity and satisfaction [98].By eliminating tasks that did not directly contribute to the quality and efficiency of patient care, pharmacists focused more on providing valuable services such as medication counseling, medication therapy management, and drug therapy reviews [79].This shift benefited patients by improving the quality of care received and allowed pharmacists to utilize their expertise and knowledge effectively.Lean management principles aim to eliminate waste, streamline processes, and improve efficiency in various industries, including healthcare.By equipping employees with the necessary knowledge and tools to identify and eliminate waste, organizations experienced significant improvements in productivity, quality, and customer satisfaction.Participants of lean management training programs learned techniques such as value stream mapping, 5S methodology, and continuous improvement, enabling them to contribute to the organization's overall success and performance [108].

Patient Engagement
The frequency of patient consultations was significantly increased as a strategic move to enhance the overall quality of healthcare delivery and to address patient concerns more promptly and effectively.This proactive approach led to improved health outcomes, as patients benefited from timely and personalized medical advice, guidance, and interventions [88].In parallel, there was a rigorous implementation of medication safety measures aimed at preventing errors and minimizing adverse drug reactions, thereby ensuring a higher standard of patient care and safety.
Additionally, efforts were made to streamline the patient discharge process, a critical step in the patient care journey.This streamlining focused on creating more efficient and transparent procedures, facilitating smoother transitions from hospital to home or next-stage care, and significantly reducing the potential for confusion or misunderstandings about post-discharge care [57].
These strategic improvements in patient consultation frequency, medication safety, and discharge processes played a pivotal role in transforming the landscape of healthcare delivery.By focusing on these critical areas, healthcare providers were able to substantially enhance patient satisfaction and safety, thereby raising the overall standard of care [92].This holistic approach to patient care not only addressed immediate health concerns but also contributed to a more patient-centric healthcare system.

Performance Metrics and Benchmarking
The utilization of KPIs significantly enhanced pharmacist productivity and, in turn, markedly improved patient care outcomes.This approach involved meticulously monitoring and assessing performance improvements within the medication dispensing cycle.Quantitating these improvements in sigma levels ensured the safety and efficiency of medication management [64,119].Additionally, there was a concerted effort to optimize the allocation of pharmacists' time across a range of critical tasks.This strategic time management maximized their productivity and played a crucial role in delivering high-quality pharmaceutical services, ultimately contributing to better patient care and service delivery [74,82].

Cultivating patient-centric lean leadership in the hospital pharmacy operations
Leadership plays a crucial role in the management of operations, and the fundamental requirement for a sustainable implementation of lean in the healthcare sector is to secure the complete backing of the organization's leadership [120].During the review process, an observation was made concerning the emergence of lean leadership in the pharmacy industry.This was accompanied by a gradual yet substantial understanding and implementation of lean philosophy principles.The fundamental concept of lean thinking guides the organization's vision to harmonize with the client's perspective.As this knowledge expands, the qualities of lean leadership emerge naturally and become inherent in the leadership approach.Lean pharmacy leaders aspire to create a culture that is unwaveringly focused on excellence, thus transforming the fundamental characteristics of leadership from traditionally authoritative and sporadic to collaborative, continuous, and empathetic toward the needs and experiences of the patients [121].This shift is not only operational but also philosophical, guiding a comprehensive transformation that incorporates the principles of Lean and Six Sigma into the structure of hospital pharmacy operations, with the ultimate goal of achieving excellence in patient care.

TABLE 3: Comparison between traditional and lean pharmacy leadership
The comparison between traditional and lean pharmacy leadership uncovered distinct approaches to managing pharmacy operations.Traditional pharmacy leadership is characterized by perceiving quality as a shared responsibility, relying on statistical averages, conducting evaluations every month, penalizing errors, being influenced by isolated incidents, suppressing disagreements, directing organizational changes, demanding management upholds standards, prioritizing cost-saving, focusing on financial outcomes, and adopting a top-down communication style.On the other hand, lean pharmacy leadership prioritizes quality as the ultimate importance, maintains stringent standards, performs daily assessments, commends the disclosure of errors, makes decisions based on empirical data, encourages open disputes, promotes collective decision-making, engages with operational staff, focuses on enhancing the quality and optimizing costs, demonstrates modesty, concentrates on patient welfare, and encourages patient engagement through direct interaction.This transition reflects the lean model as a more dynamic, inclusive, and patient-centered approach.

Lean Six Sigma DMAIC tools framework for hospital pharmacy
The systematic review undertaken for this research paper ended in the development of a condensed version of the LSS DMAIC tool framework, specially adapted for implementation in hospital pharmacy settings.This modification of the LSS DMAIC model is presented in Figure 11 as a concise and informative flow diagram [122].This diagram serves as an important visual guide that effectively presents the sequential phases of defining, measuring, analyzing, improving, and controlling the strategic tools associated with each phase.As a result, it provides a structured approach to process improvement within hospital pharmacy environments.

FIGURE 11: Lean Six Sigma DMAIC tools framework
The template downloaded from SlideGeeks [122]  In the defining phase, significant practices such as Gemba walks and the VOC are emphasized.Gemba walks involve visiting the work site to directly observe daily operations and identify areas for potential improvement.Meanwhile, the VOC technique focuses on comprehending the needs, expectations, and experiences of both patients and staff, which is crucial for establishing meaningful and patient-centered improvement goals.
The measuring phase employs tools like brainstorming sessions, enabling the collaborative generation of ideas, and the identification of key metrics for monitoring.Additionally, process flowcharts are utilized to visually represent existing workflows, with the aim of identifying inefficiencies and redundancies.These tools facilitate a comprehensive understanding of the current state of pharmacy operations.
During the analyzing phase, the use of cause-and-effect diagrams aids in determining the root causes of identified problems.These diagrams, supported by FMEA, enable a detailed exploration of potential failure points and their impacts on pharmacy processes, thereby laying the groundwork for targeted improvements.
In the improving phase, strategies such as Kaizen and the design of experiments are implemented.Kaizen emphasizes continuous, incremental improvements, focusing on enhancing efficiency and quality through manageable steps.Meanwhile, the design of experiments method allows for systematic experimentation to assess the effects of various changes on process outcomes, ensuring that improvements are data-driven and effective.
Last, the control phase incorporates statistical process control (SPC) and the establishment of standard operating procedures (SOPs).SPC is utilized to monitor process performance and sustain the gains achieved in previous phases, while SOPs guarantee consistency, safety, and compliance in daily pharmacy operations.
This comprehensive LSS DMAIC framework, as represented in the diagram, encapsulates the fundamental principles and methods of LSS, tailored specifically to address the unique needs and challenges of hospital pharmacies.By following this structured approach, hospital pharmacies are equipped to enhance their operational efficiency, service quality, and overall patient care.Consequently, this diagram and the accompanying explanation constitute a crucial component of the research paper, providing valuable insights and a practical roadmap for quality improvement initiatives in hospital pharmacy settings.

Study strengths and limitations
The review was characterized by a broad scope and rigorous PRISMA-guided methodology, including a standard review checklist and a four-phase flow diagram [27], providing a view of diverse management strategies with in-depth insights relevant to hospital pharmacy practice and policy-making.Incorporating the Six Sigma DMAIC cycle into the review process offered a potentially innovative approach, providing a well-defined procedure that integrated various established LSS methodological tools, thereby serving as valuable guidance for quality managerial decision-making in the pharmacy field [123].
However, the study faced limitations such as heterogeneity among the included studies and language bias, affecting the generalizability of findings.The evaluation solely encompassed written documents in English, which might lead to underestimation of research conducted in other languages.The primary focus of the review and its query was based on observation, utilizing information to ascertain the LSS tools employed in hospital pharmacies.Therefore, the quantity of objective verification to validate these findings was relatively limited, comprising solely of results derived from the studies that were considered.Additionally, the search algorithm for Lean and Six Sigma strategies implemented in hospital pharmacy services was limited to only the sections of title-abstract-keywords, which could constrain the results obtained.The industry's dynamic progression and the omission of grey literature may have influenced the review's completeness to some extent.

Recommendation for future studies
In future research, it is possible to explore further theories and methodologies related to operations management, specifically within hospital pharmacy.Investigating these possibilities can improve quality management in pharmacy and healthcare.Moreover, future evaluations might consider adding objective factors and challenges for Lean and Six Sigma implementation.Eventually, there is a clear requirement for future empirical investigations to comprehensively examine and clarify the utilization of innovative management systems and applications driven by artificial intelligence and robotics [124].

Conclusions
The author's primary contribution was gathering and analyzing substantial information about LSS tools and their impact on hospital pharmacy performance.This effort was achieved by thoroughly examining literature published between 2009 and 2023, accompanied by detailed assessment, deep analysis, and subsequent recommendations.
This systematic review figured out that implementing diverse Lean and Six Sigma management strategies was pivotal in enhancing the quality aspect of hospital pharmacy operations management.The review demonstrated the effectiveness of LSS methodologies in improving operational efficiency and attaining positive results in hospital pharmacies worldwide.It also provided insight into the dynamic interaction between Lean and Six Sigma approaches and their substantial impact on the quality of pharmacy operations and patient services.The findings emphasized the crucial role of context-specific strategies, CSFs, and the imperative for ongoing adaptation and innovation in management practices to align with the changing needs of healthcare.Moreover, the review provided quality-focused tools and techniques, CTQ elements, and KPIs for process enhancement.
This thorough consolidation has the potential to enhance the global comprehension of quality management in hospital pharmacies and become an integral reference for professionals and policymakers committed to improving pharmacy services and raising the standard of patient care.

FIGURE 1 :
FIGURE 1: PRISMA 2020 flow diagram for the selection process in the systematic review PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses Abbassi etal.[35] cost management.In 90 days, ICU medication reconciliation improved with increases in all units, including a 50% rise in the medical ICU and neurological critical care unit.

22 interventions
staff in the A shift was reduced from 5 to 4, work start times for A Six Sigma in its infancy with challenges such as lack of training and awareness et al.Cureus 16(3): e57176.DOI 10.7759/cureus.innurse journeys to the pharmacy for drug collections post-intervention, maintained after 18 months; significant reduction in nursing time spent on controlled drug collections and deliveries, leading to a savings of 661.patient safety.An observational (transversal) and retrospective study in a general hospital of 2024 Sallam et al.Cureus 16(3): e57176.DOI 10.7759/cureus.sevenmonths, 63 orders for OC were placed for 45 patients, all reviewed by pharmacists (rate of review 100%), resulting in pharmacist time: prescription preparation (39.8%), clinician interaction (21.5%),EMR operations (14.8%), and patient interaction (18.7%).Pharmacists invested the most time in al. Cureus 16(3): e57176.DOI 10.7759/cureus.5717615 of 40 of pharmacist time spent handwriting medication labels.The average value quotient was 40.3%, indicating that pharmacists spend more than half of their time on tasks they consider non-valuetime, Moreover, (c) reduced medication waste.Increase of 29% in nursing team's satisfaction.Reduction 2.5 h/day in the time spent by the nursing staff to locate medications.-Reduction in the nursing waiting time to receive as 5S and value-stream Cost savings, SPA waste reduction yielded an annual saving of $275,500.There Implement lean 2024 Sallam et al.Cureus 16(3): e57176.DOI 10.7759/cureus.
Sallam et al.Cureus 16(3): e57176.DOI 10.7759/cureus.57176Annual Trend of Published Studies from 2009 to 2023 illustrates the yearly progression of research papers identified through a review search strategy over fifteen years, from 2009 to 2023.

FIGURE 3 :
FIGURE 3: Column chart for the annual trend of published studies from 2009 to 2023

FIGURE 4 :
FIGURE 4: Global geographical distribution of pharmacy Lean Six Sigma studies: 2009-2023Map generated using the "Insert Map Chart" option in Microsoft Excel 2021[33]

FIGURE 8 :
FIGURE 8: Pareto chart displaying Lean Six Sigma tools and techniques used in the context of hospital pharmacyDMAIC: Define, measure, analyze, improve, and control; 5S: Sort (Seiri), set in order (seiton), Shine (Seiso), standardize (Seiketsu), and sustain (shitsuke); FMEA: Failure mode and effect analysis; RCA: Root cause analysis; VSM: Value stream mapping; Gemba Walk: Japanese term meaning the physical workplace; Kaizen: Japanese term meaning continuous improvement; PDCA: Plan-do-check-act; BSC: Balanced scorecard; Kanban: Japanese term meaning a visual work management system card; Pareto: (also known as the 80/20 rule) is a phenomenon states that roughly 80% of outcomes come from 20% of causes; PDSA: Plan-do-study-act; SIPOC: Suppliers, inputs, processes, outputs, and customers with a valid subscription permission to all the website content Credit: Dr. Mohammed Sallam Gemba Walk: Japanese term meaning the physical workplace; PDCA: Plan-do-check-act; ANOVA: Analysis of variance; T-test: A statistical test used to compare the means of two groups; 5S: Sort, Set in order, Shine, Standardize, and Sustain; Kaizen: Japanese term meaning continuous improvement; Kanban: Japanese term meaning a visual work management system card; DMAIC: Define, measure, analyze, improve, and control

Table 2
concisely organizes and presents this array of information for quick reference and comparison.

TABLE 2 : Characteristics and outcomes of included studies
BMC: BioMed Central; FMEA: Failure mode and effects analysis; RPN: Risk priority number; DMAIC: Define-measure-analyze-improve-control

Table 3
compares conventional and lean approaches to pharmacy leadership, focusing on quality, standards, and engagement.