European Journal of Cardiovascular Medicine

Chronic kidney disease (CKD) represents a global health burden with a significant impact on morbidity and mortality rates worldwide. The final stage of CKD, end-stage renal disease (ESRD), necessitates renal replacement therapies such as maintenance haemodialysis for sustaining life. Haemodialysis remains a cornerstone in the management of ESRD, providing an essential lifeline for patients while also posing considerable challenges, including a heightened risk of hospitalization due to complications associated with the disease and treatment process [1].

The burden of hospitalization among ESRD patients on maintenance haemodialysis is substantial, reflecting both the severity of the underlying renal condition and the complexities involved in the management of such patients. Hospital admissions are not only a marker of morbidity but also significantly impact the quality of life, healthcare costs, and overall prognosis for these individuals [2]. Understanding the etiology, frequency, and outcomes of these hospitalizations is crucial for developing strategies to reduce their incidence and improve care outcomes.

Etiologically, hospital admissions in this cohort are often precipitated by a myriad of factors. These include complications related to the haemodialysis procedure itself, such as access-related infections or thrombosis, cardiovascular events, fluid 

overload, and electrolyte imbalances, alongside infections, and the broader implications of comorbid conditions [3]. The frequency and nature of these admissions reflect the intricate balance required in managing ESRD and the inherent risks associated with maintenance haemodialysis.

Moreover, the outcomes of hospitalization in this patient population are a focal point of concern. Prolonged hospital stays, readmissions, and increased mortality rates are notable challenges. The quality of care, including the management of haemodialysis and associated conditions during hospital stays, directly influences these outcomes. Consequently, analysing the factors contributing to hospitalization and their correlation with hospitalization outcomes is imperative for enhancing patient care and optimizing resource utilization in tertiary care centers [4].

In this context, our study aims to delve into the etiology, frequency, and outcomes of hospital admissions among patients undergoing maintenance haemodialysis in a tertiary care setting. Specifically, we seek to identify the predominant causes leading to hospitalization, evaluate the frequency of these admissions, and assess the resulting outcomes. Additionally, our analysis will explore the various factors contributing to hospitalization, examining their interrelations and impact on the quality of care and patient prognosis. Through this comprehensive study, we aim to contribute valuable insights to the existing literature, fostering improvements in the management and care strategies for ESRD patients on maintenance haemodialysis.

Aims and Objectives

The primary aim of the study was to investigate the etiology, frequency, and outcomes of hospital admissions among patients undergoing maintenance haemodialysis for End-Stage Renal Disease (ESRD). This comprehensive analysis sought to uncover the underlying reasons leading to hospitalizations, the regularity of these occurrences, and their subsequent impact on patient prognosis. Additionally, the study aimed to analyse the various factors contributing to hospitalization, including but not limited to demographic details, duration of illness, and presence of comorbidities, and to examine their correlation with the outcomes of hospitalization. The objective was to delineate the complex interplay of factors that lead to hospital admissions and to assess how these factors influence the length of hospital stay and the ultimate health outcomes for patients on maintenance haemodialysis.

This section delineated the methodological framework employed in conducting this prospective observational study. The research was meticulously designed to gather and analyze data from a cohort of 130 patients receiving maintenance haemodialysis at Rajiv Gandhi Government General Hospital over a six-month period from April 2022 to September 2022. The inclusion criteria specified that participants had to be adults over 18 years of age, undergoing maintenance haemodialysis at the specified facility. Exclusion criteria were set to omit patients unwilling to participate, those under 18 years of age, and patients who had initiated regular haemodialysis less than three months prior to the commencement of the study.

After obtaining ethical clearance and ensuring informed consent in Tamil, the study utilized a previously designed proforma for data collection. This proforma facilitated the systematic recording of demographic details, clinical history, and a comprehensive range of variables including the etiology of chronic kidney disease (CKD), duration of CKD and maintenance haemodialysis, dialysis frequency, vascular access type, and a spectrum of comorbid conditions. Laboratory and diagnostic parameters such as baseline haemoglobin, urea, creatinine levels, estimated glomerular filtration rate (eGFR) using the CKD-EPI creatinine 2021 formula, and serum electrolytes were meticulously documented alongside echocardiography findings and information pertaining to drug and fluid compliance. During hospitalization, the reason for admission, duration of stay, and outcome (discharge or death) were collected to analyse the factors responsible for hospitalization among this patient cohort.

The study was conducted in collaboration with the Institute of Nephrology, Department of Biochemistry, and Institute of Cardiology, ensuring a multidisciplinary approach to data collection and analysis. Statistical analysis was performed using SPSS V.17 for Windows, with the collected data being formulated into a master chart in Microsoft Office Excel. The analytical process involved calculating frequencies, range, mean, standard deviation, and determining statistical significance through student 't' test, one-way ANOVA, Pearson correlation, and chi-square test, with a p-value of < 0.05 considered significant. The study declared no conflict of interest and did not receive any financial support.

In the conducted study, the demographic and gender distribution showcased a total of 130 patients undergoing maintenance haemodialysis due to end-stage renal disease (ESRD). The age distribution revealed the largest group of patients was between 41-50 years, accounting for 32.3% of the study population, followed by the 31-40 years age group at 22.3%. Patients over 61 years and those under 20 years represented the smallest groups, constituting 15.4% and 3.1% of the population, respectively. In terms of gender, males significantly outnumbered females, with 87 males (66.9%) compared to 43 females (33.1%).

Clinical characteristics and comorbidities of the cohort were also examined. Hypertension (HTN) was the most prevalent comorbidity, present in 87.7% of the patients, followed by diabetes mellitus (DM) and coronary artery disease (CAD), affecting 28.5% and 20.8% of the patients, respectively. Less common conditions included thyroid disorders (9.2%), old pulmonary tuberculosis (OLD PTB) (10.8%), systemic lupus erythematosus (SLE) (3.8%), and seizure disorders (2.3%). The analysis of haemoglobin levels indicated that 61.5% of the patients had levels above 8 g/dL, while 38.5% had levels below this threshold. Similarly, serum albumin levels were above 3.4 g/dL in 70.0% of the patients and below 3.4 g/dL in 30.0%.

Hospitalization outcomes and readmission rates were closely monitored, with 8 deaths (6.2%) and 70 discharges (53.8%). A notable 88.5% of the study population did not experience readmission, whereas 11.5% were readmitted during the study period. The causes of hospitalization varied, with acute pulmonary edema being the most common, accounting for 31.4% of the hospitalizations, followed by anasarca (11.4%) and uremic gastritis (8.6%). Other causes included accelerated hypertension, active pulmonary tuberculosis, acute diarrheal disease, acute febrile illness, acute haemorrhagic stroke, acute myocardial infarction, and urinary tract infections.

The duration of renal disease and maintenance haemodialysis (MHD) before hospitalization was analyzed, revealing that 46.2% of patients had been diagnosed with renal disease for 5.1-10 years, and 49.2% had been on MHD for 1.1-5 years. Regarding the frequency of MHD, the majority (68.5%) received treatment twice a week, 30.8% three times a week, and a minority (0.8%) once a week.

Correlations with hospitalization showed significant findings. Patients younger than 60 years had a higher rate of hospitalization compared to those older than 60 years, with a p-value of 0.047. Haemoglobin levels showed a trend towards higher hospitalization rates in patients with levels below 8 g/dL compared to those with levels above 8 g/dL, although this did not reach statistical significance (p=0.089). No significant correlation was found between serum albumin levels and hospitalization rates (p=0.513). Cardiac abnormalities were significantly associated with increased hospitalization rates (p<0.0001), as was the frequency of MHD, with those undergoing dialysis three times a week showing higher hospitalization rates compared to twice a week (p=0.004). The presence of diabetes mellitus, the duration of renal disease, and the duration of MHD did not significantly affect hospitalization rates, with p-values of 0.139, 0.39, and 0.159, respectively.

The mean duration of hospital stay was influenced by several factors. Patients with haemoglobin levels below 8 g/dL and those with serum albumin levels below 3.4 g/dL had longer stayed, averaging 7.12 and 7.43 days, respectively. In contrast, patients undergoing MHD once a week had the shortest average stay of 3.00 days. The presence of diabetes mellitus and cardiac abnormalities also affected the length of stay, though not uniformly.

The study further analyzed mortality causes among the hospitalized patients. Acute pulmonary edema was the leading cause of death, responsible for 37.5% of all fatalities, followed by acute haemorrhagic stroke and uremic encephalopathy, each contributing to 25.0% of the deaths. Sepsis or septic shock was responsible for 12.5% of mortality.

This detailed analysis of the outcomes of hospitalization in patients on maintenance haemodialysis in a tertiary care center underscores the complex interplay of demographic factors, clinical characteristics, and comorbidities in influencing hospitalization rates, readmission rates, and mortality among this vulnerable population

The study's findings underscore the significant burden of hospitalization among patients undergoing maintenance haemodialysis for end-stage renal disease (ESRD), a concern that resonates with global observations on the management of chronic kidney disease (CKD) and its terminal phase. The demographic distribution aligns with broader epidemiological data, indicating a prevalence of ESRD in middle-aged populations, particularly among males [5]. This gender disparity is reflected in the literature, where males often demonstrate a higher incidence of CKD and its progression to ESRD, potentially attributed to both biological factors and lifestyle choices [6].

Hypertension (HTN) emerged as the most prevalent comorbidity, present in 87.7% of patients, a figure that significantly exceeds the global prevalence estimates of HTN among the general population. This underscores the well-documented role of HTN as both a cause and consequence of CKD, necessitating aggressive management strategies to mitigate its impact on disease progression and associated hospitalizations [7]. Similarly, the high prevalence of diabetes mellitus (DM) among the study cohort (28.5%) corroborates the established relationship between DM and CKD, highlighting DM as a leading cause of ESRD worldwide [8].

The significant association between cardiac abnormalities and increased hospitalization rates, noted in this study, reflects the intricate link between heart disease and CKD, often referred to as the cardiorenal syndrome. Patients with ESRD are at an elevated risk of cardiovascular morbidity and mortality, a risk compounded by the presence of cardiac abnormalities [9]. These findings emphasize the necessity for integrated care approaches that concurrently address renal and cardiovascular health in this patient population.

Interestingly, the study did not find a statistically significant correlation between serum albumin levels and hospitalization rates (p=0.513), a result that contrasts with previous research suggesting hypoalbuminemia as a predictor of poor outcomes in ESRD patients [10]. This discrepancy may point to variations in patient demographics, disease management practices, or nutritional interventions across different care settings, warranting further investigation.

The high frequency of acute pulmonary edema as a cause of hospitalization highlights fluid management challenges in haemodialysis patients. Fluid overload is a common complication of ESRD, often necessitating hospitalization for acute management [11]. This underscores the importance of meticulous fluid balance monitoring and individualized dialysis regimens to prevent such adverse outcomes.

The study's mortality analysis revealed acute pulmonary edema, acute haemorrhagic stroke, and uremic encephalopathy as leading causes of death, underscoring the severe complications that can arise in the context of ESRD and maintenance haemodialysis. These findings echo the literature, which cites cardiovascular events, infections, and cerebrovascular accidents among the top causes of death in this patient population [12].

The study comprehensively delineates the multifaceted challenges and outcomes associated with hospitalization in patients undergoing maintenance haemodialysis for end-stage renal disease (ESRD) in a tertiary care center. Key findings illustrate the significant burden of comorbid conditions, notably hypertension (87.7%) and diabetes mellitus (28.5%), underscoring their pivotal role in the management and prognosis of ESRD. The demographic profile, with a predominant age group of 41-50 years (32.3%) and a higher prevalence in males (66.9%), aligns with global trends in ESRD epidemiology.

The correlation analyses reveal critical insights, particularly the significant impact of cardiac abnormalities on hospitalization rates (p<0.0001) and the notable association between the frequency of maintenance haemodialysis and hospital admissions (p=0.004). Furthermore, the leading causes of mortality identified—acute pulmonary edema (37.5%), acute haemorrhagic stroke, and uremic encephalopathy (each contributing to 25.0% of deaths)—highlight the severe complications confronting this patient cohort.

These findings emphasize the necessity for a holistic, multidisciplinary approach in managing ESRD, focusing not only on renal replacement therapy but also on rigorous control of comorbid conditions, tailored fluid management strategies, and proactive measures to mitigate cardiovascular risk factors. Such an approach is paramount to improving clinical outcomes, reducing hospitalization rates, and enhancing the quality of life for patients on maintenance haemodialysis.

1. Collins AJ, Foley RN, Gilbertson DT, Chen SC. The state of chronic kidney disease, ESRD, and morbidity and mortality in the first year of dialysis. Clin J Am Soc Nephrol. 2009;4(Suppl 1):S5-S11.
2. Ishani A, Xue JL, Himmelfarb J, Eggers PW, Kimmel PL, Molitoris BA, Collins AJ. Hospitalizations in dialysis patients: analysis of the 1997 United States Renal Data System (USRDS). Am J Kidney Dis. 2007;50(3):419-430.
3. Saran R, Robinson B, Abbott KC, Agodoa LYC, Bhave N, Bragg-Gresham J, et al. US Renal Data System 2016 Annual Data Report: Epidemiology of Kidney Disease in the United States. Am J Kidney Dis. 2017;69(3 Suppl 1):A7-A8.
4. Foley RN, Wang C, Ishani A, Collins AJ. Blood pressure control in chronic kidney disease: is less more? J Am Soc Nephrol. 2005;16(6):1782-1789.
5. United States Renal Data System. 2020 USRDS Annual Data Report: Epidemiology of Kidney Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2020.
6. Carrero JJ, Hecking M, Ulasi I, Sola L. Sex and gender disparities in the epidemiology and outcomes of chronic kidney disease. Nat Rev Nephrol. 2018 Mar;14(3):151-164.
7. Sarafidis PA, Ruilope LM. Insulin resistance, hyperinsulinemia, and renal injury: Hypertension and the kidney. Hypertension. 2006 Sep;48(2):209-10.
8. Reutens AT. Epidemiology of Diabetic Kidney Disease. In: Diabetic Nephropathy. 2019.
9. Ronco C, Haapio M, House AA, Anavekar N, Bellomo R. Cardiorenal syndrome. J Am Coll Cardiol. 2008 Nov 4;52(19):1527-39.
10. Kalantar-Zadeh K, Kilpatrick RD, Kuwae N, McAllister CJ, Alcorn H Jr, Kopple JD, Greenland S. Revisiting mortality predictability of serum albumin in the dialysis population: Time dependency, longitudinal changes and population-attributable fraction. Nephrol Dial Transplant. 2005 Sep;20(9):1880-8.