Epidemiology and Clinical Characteristics of Chronic Kidney Disease in Bihar: A Cross-Sectional Study From a Single Center

Background Chronic kidney disease (CKD) is a major public health concern globally, often co-occurring with type 2 diabetes (T2D), hypertension (HTN), and cardiovascular disorders (CVD), which complicate its management and exacerbate outcomes. This study aims to investigate the epidemiological and clinical characteristics of CKD in Bihar, a region often underrepresented in national data. Methods This cross-sectional observational study was conducted at the Department of Nephrology, Indira Gandhi Institute of Medical Sciences (IGIMS) in Patna, Bihar, India. A total of 2,534 adult patients of both sexes who consented to participate were included. We collected demographic and clinical data, calculated the estimated glomerular filtration rate using the CKD-Epidemiology (CKD-EPI) Collaboration creatinine equation, and classified CKD stages. Statistical analyses were performed using IBM SPSS Statistics for Windows, version 29.0.2.0 (IBM Corp., Armonk, NY). Result The majority of the study population was male (66.5%), with a significant number residing in rural areas (76.8%). The prevalent causes of CKD included HTN (41.2%), chronic tubulointerstitial nephritis (31.8%), and T2D (23.2%). Approximately one-third of patients were in the early stages (Stages 1 and 2) of CKD. A high prevalence of anemia was noted across all stages, increasing significantly with glomerular filtration rate (GFR) reduction. Treatment analysis showed suboptimal use of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARBs) and other standard treatments like diuretics and statins, especially among T2D patients. Conclusion Chronic kidney disease in Bihar affects predominantly young males and is associated with significant rural prevalence and comorbidities like T2D, HTN, and CVD. Our results highlight the need for improved management practices, especially in the use of ACEi/ARBs and erythropoiesis-stimulating agents, to slow GFR reduction. Further multicentric, community-based studies are recommended to provide a more comprehensive understanding of CKD in Bihar.


Introduction
Chronic kidney disease (CKD) significantly contributes to morbidity and mortality, often coexisting with type 2 diabetes (T2D), hypertension (HTN), and cardiovascular disorders (CVD).These conditions interact, complicating management and worsening outcomes.Chronic kidney disease predicts poor quality of life, cognitive decline, frequent hospitalizations, and substantial healthcare costs [1].Its global prevalence has increased by 29.3% from 1990 to 2017, making it a major public health concern [2,3].In 2017, an estimated 697.5 million people worldwide (9.1% prevalence) suffered from CKD, with India alone accounting for 115.1 million cases, the second highest after China (132.2 million).The growing burden of CKD has moved it to the 12 th leading cause of death globally in 2017, up from the 17 th in 1990, underscoring its escalating impact [3].In India, deaths attributed to CKD rose from 0.59 million in 1990 to 1.18 million in 2016 [4].In lower-and middle-income countries, including India, CKD is frequently linked to infectious diseases, glomerulonephritis, and the inappropriate use of nephrotoxic agents like non-steroidal anti-inflammatory drugs, certain antibiotics, and traditional remedies.The absence of a central CKD registry in India likely leads to underestimations of its true incidence and prevalence.Previous studies have examined CKD's epidemiology and clinical features across India [5][6][7][8][9], yet none included data from Bihar.This study aims to fill that gap by assessing the epidemiological and clinical characteristics of CKD in Bihar.

Study design
We conducted this cross-sectional observational study at the Department of Nephrology, Indira Gandhi Institute of Medical Sciences (IGIMS) in Patna, Bihar, India, over 18 months.The institutional ethics committee of IGIMS approved the study (approval no.178/IEC/IGIMS/2021, dated June 26, 2021).We included patients with CKD aged over 18 years from both sexes who consented to participate, recruited from July 2021 to December 2023.We excluded individuals under the age of 18, pregnant women, patients with acute kidney injury, malignancy, psychiatric illnesses, or those who refused consent.We reviewed the files of 3,127 CKD patients, of whom 2,534 patients were finally included in this study.The rest of the patients were excluded due to refusal of consent, incomplete baseline laboratory investigations hindering interpretation, or discrepancies in data recording.

Data collection and statistical analysis
At their initial visit, we recorded the patients' demographic and clinical parameters.We obtained laboratory data from the hospital's informatics system and documented them in a Microsoft Excel spreadsheet (Microsoft Inc., Redmond, WA).At this institute, creatinine levels (in either serum or urine samples) were measured using the colorimetric modified Jaffe's method.We calculated the estimated glomerular filtration rate (eGFR) using the CKD-Epidemiology (CKD-EPI) Collaboration creatinine equation [10].Urine routine analysis and urine protein estimation data were retrieved.Urine albumin was assessed using the dye-binding bromocresol purple (BCP) method.The urine albumin-creatinine ratio (ACR) was then determined and used to classify albuminuria as follows: normal to mildly increased (A1; ACR < 30 mg/gram), moderately increased (A2; ACR 30-299 mg/gram), and severely increased (A3; >300 mg/gram).We defined CKD as abnormalities in kidney structure or function persisting for more than three months with health implications [10].We classified CKD stages based on eGFR: Stage 1 (>90 ml/minute), Stage 2 (89-60 ml/minute), Stage 3a (59-45 ml/minute), Stage 3b (30-44 ml/minute), Stage 4 (29-15 ml/minute), and Stage 5 (<15 ml/minute).We defined anemia as hemoglobin levels below 13.0 g/dl in men and below 12.0 g/dl in women.The severity of anemia was categorized as follows: mild (hemoglobin concentration 10-12 grams/deciliter (13 grams/deciliter in males)), moderate (hemoglobin concentration < 10 to 8 grams/deciliter), and severe anemia (hemoglobin concentration < 8 grams/deciliter) [10].We documented treatment details for each patient and analyzed all data using IBM SPSS Statistics for Windows, version 29.0.2.0 (IBM Corp., Armonk, NY) for further analysis.The normality of variables was checked by the Kolmogorov-Smirnov test.The results of non-parametric variables were presented as medians and interquartile ranges (IQRs).The Chisquare or Fisher's exact test was used to compare the categorical variables.The results of the Chi-square test were tabulated as frequency and percentage.A p-value <0.05 was considered statistically significant.

Discussion
This hospital-based cross-sectional study investigated the prevalence, epidemiology, demographic characteristics, comorbidities, clinical staging, management, and prescription patterns of CKD in Bihar, one of India's poorer states with suboptimal health indices [11].We enrolled 2,534 participants, with a median age of 41 years (IQR: 28 to 55 years).This age is comparable to findings from other Indian studies: 41.4 ± 12.7 years in Chennai, 44.4 ± 13.9 years in Delhi, and 50.1 ± 14.6 years in the Center for Cardiometabolic Risk Reduction in South Asia (CARRS) surveillance study by Anand et al. [12].The male-to-female ratio in our study was 1.98, similar to the 2.3 ratio reported in the Indian CKD registry [7].Nayak-Rao in Assam found 70% male prevalence in a cohort of 334 CKD patients [13], while the CARRS surveillance study observed near equal or slightly higher CKD prevalence in females (7.5% vs. 7.7%) [12].These variations in gender distribution may be attributable to occupational differences, a higher likelihood of males seeking treatment, and societal gender biases in healthcare access in Bihar.In patriarchal societies, where men often serve as primary earners, their health tends to be prioritized.
Our study found that 76.8% of patients lived in rural areas, and 63.6% had received a formal education, aligning with findings from the Indian Chronic Kidney Disease (ICKD) Phase 1 study, where approximately two-thirds of patients were from rural areas and approximately 73% were educated [9].The literacy rate in Bihar is similarly reported at 61.8% [14].We observed socioeconomic disparities between rural and urban CKD patients: rural patients typically had lower education levels, were often employed in unskilled or semiskilled physical labor, and earned less.Urban CKD patients, while generally more educated, also faced unemployment and lower earnings.These findings are echoed in the ICKD study, which noted higher illiteracy rates among rural CKD patients (33.21% vs. 14.6% in urban areas) and higher annual incomes among urban residents [9].
Our findings suggest that CKD is prevalent among individuals with lower socioeconomic status, regardless of geographical location.This trend could be linked to limited access to healthcare facilities in remote rural areas, driven by both a lack of awareness and affordability.The ICKD study indicated no significant difference in the prevalence of comorbidities such as T2D, HTN, or CVD [9].This uniformity implies that many patients present at later stages of the disease due to the distance from tertiary healthcare facilities and the high treatment costs, which are predominantly out-of-pocket in India.Rajapurkar et al. also noted that insufficient health facilities and awareness often prevent early diagnosis of CKD, leading to patients from rural areas presenting at more advanced stages, which increases treatment costs and worsens the overall prognosis [7].In our study, the majority (n = 1,380, 85.6%) of patients had mild (A1) to moderate (A2) levels of albuminuria, while only 307 (14%) had severely increased albuminuria (A3).Among diabetic patients, the majority (204, 50.7%) had severely increased albuminuria, whereas the majority (n = 1637, 94%) of nondiabetic patients had mild (A1) to moderate (A2) levels of albuminuria.Our observation supports the notion that diabetic patients present with albuminuria early in the course of the disease.
In our study, two-thirds of the patients were diagnosed with early CKD (Stages 1 or 2).This classification was based on including proteinuria of more than three months as a diagnostic criterion for CKD, similar to the approach used in the Screening and Early Evaluation of Kidney Disease (SEEK) study [8].In contrast, a study from Chennai defined CKD using an eGFR cut-off of less than 80 ml/minute [5], and Agarwal et al. in Delhi used a serum creatinine threshold greater than 1.8 mg/dL [6].Since serum creatinine and creatinine-based equations can be unreliable in accurately measuring kidney damage, these studies likely underestimated the number of patients with early-stage CKD who exhibited only proteinuria with normal serum creatinine levels.According to the KDIGO guidelines, such patients should be classified as having CKD [15].
Variations in the definitions and inclusion criteria for CKD across different studies have led to disparate prevalence rates.Our study identified the following prevalence rates for CKD stages: 33 .These disparities may be attributable to differences in inclusion criteria and a lack of awareness among the population and local practitioners about CKD, resulting in delayed evaluation of kidney function.Similar trends of more advanced disease and severe anemia in T2D patients have been reported in other studies [12,18].
The prevalence of HTN in our study was significantly lower than that reported in the ICKD study and by Rao et al. [9,13], but it was similar to figures from the Indian CKD registry and the CARRS registry [7,12].We have compared the baseline characteristics of our study with those of other national and international CKD registries in Table 7 [7][8][9]19,20].Similar to findings from the Indian CKD registry and SEEK study [8], approximately two-thirds of our CKD patients had an annual income of less than Rs.100,000.Bihar's per capita income in the financial year 2022-23 was Rs. 54,000, notably lower than the national average of Rs. 172,000, making it the state with the lowest per capita income among larger Indian states [21].Consequently, financial constraints may impede access to healthcare, leading to a higher prevalence of CKD, delayed diagnoses, and progression to the advanced stages of the disease.
In our cohort, only 320 (12.6%) patients were prescribed ACEi or ARBs, with T2D patients twice as likely to receive these medications compared to non-diabetic patients.This contrasts with the 20.5% reported by Tuttle et al. [22].Additionally, statins were prescribed to 1,019 (40.2%) of our patients, which differs from the 17.7% reported in Tuttle et al.'s study.These discrepancies highlight a gap in the optimal management of CKD, underscoring the need to promote the use of ACEi/ARBs to slow GFR reduction.The prescription of statins, particularly in T2D and CAD patients, reflects standard practice.
Our study also observed nephrolithiasis in 256 (10.1%) patients, with 60% experiencing bilateral obstruction which is higher than the 5.2% prevalence reported in the SEEK study [8].This suggests a potential link between bilateral renal calculi and CKD progression in both T2D and non-diabetic patients.Typically, unilateral renal calculi present with renal colic and normal renal function, leading patients primarily to urology outpatient departments.
The most common symptoms in our cohort were weakness (n = 704; 27.9%) and uremic symptoms such as anorexia, nausea, and vomiting (n = 570; 22.5%).Four hundred ninety-four patients (19.5%) were asymptomatic, discovered through incidental findings of proteinuria or other laboratory abnormalities.Galhotra et al. reported higher frequencies of these symptoms [23].
Anemia was prevalent in 2,138 (84.4%) of our patients, with a mean hemoglobin concentration of 8.42 ± 2.2 g/dL.Severe anemia (hemoglobin concentration <8 g/dL) was more common and severe in Stage 5 CKD compared to Stage 3. The proportion of severe anemia was significantly higher in Stage 5 (n = 67; 40%) than in Stages 1 and 2 (n = 106, 12.5%, and n = 129, 15.2%, respectively), aligning with US Renal Data System 2023 data [23].The high prevalence of anemia may reflect underlying malnutrition and iron deficiency, particularly in economically disadvantaged rural areas.Only 338 (13.4%) anemic patients received erythropoiesis-stimulating agents, and a mere 165 (6.5%) received blood transfusions, indicating inadequate treatment for anemia.This low transfusion rate could be attributed to Bihar's scarcity of blood donations, compounded by myths about post-transfusion weakness and a general reluctance to engage with health services.
Regarding dialysis, among 106 Stage 5 CKD patients, only 14 (13%) had arteriovenous fistulas for hemodialysis, with the remainder using temporary non-tunneled internal jugular catheters.Twenty-nine patients (27%) did not receive regular dialysis due to the high demand and limited capacity at government centers, leading to inadequate treatment and severe outcomes.Bihar's shortage of nephrology services is exacerbated by the fact that only approximately 25 nephrologists are available for a population of 120 million, predominantly in urban areas.
Our study had several important limitations.Being a hospital-based study, the findings cannot be extrapolated to the general population.Despite being conducted at the largest government tertiary care institute in Bihar, which attracts a substantial patient influx from neighboring states and even Nepal, the results may not apply universally to other centers.Additionally, as IGIMS is a public sector hospital, it may disproportionately represent patients from lower socioeconomic strata, potentially not reflecting the condition of the more affluent segments of society.These factors limit the generalizability of our findings and suggest the need for caution in interpreting the scope of CKD prevalence and management practices derived from this single-center study.

Conclusions
This study aimed to examine the epidemiological and clinical features of CKD in Bihar, a region frequently overlooked in national data.Our study observed that CKD patients in Bihar are predominantly young males, with a significant proportion residing in rural areas characterized by low literacy and income levels.Common comorbidities among these patients included T2D, HTN, and CAD, and they often presented at the early stages of CKD.Anemia was more prevalent and tended to be more severe in the advanced stages of the disease.The underuse of ACEi, ARBs, and erythropoiesis-stimulating agents underscores a critical area for improvement in clinical practice.To gain a deeper understanding of the prevalence, etiology, and outcomes of CKD in this region, conducting a larger, multicentric, community-based study with long-term follow-up is essential.

Table 1
presents a comprehensive breakdown of these characteristics.

TABLE 2 : Distribution of anemia and its severity among participants according to CKD stages (N = 2,138)
CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate

Table 3
presents detailed demographic comparisons and additional statistical data.

Table 6
provides additional socioeconomic data.

TABLE 7 : Basic clinical and epidemiological characteristics of major CKD registries CKD
: chronic kidney disease; T2D: type 2 diabetes; CVD: cardiovascular disease; DKD: diabetic kidney disease; HTN: hypertension; CGN: chronic glomerulonephritis; CIN: chronic interstitial nephritis; PKD: polycystic kidney disease; eGFR: estimated glomerular filtration rate; SEEK: Screening and Early Evaluation of Kidney Disease; ICKD: Indian Chronic Kidney Disease; KNOW-CKD: KoreaN Cohort Study for Outcomes in Patients With Chronic Kidney Disease; CRIC: Chronic Renal Insufficiency Cohort; NA: not applicable