Supplementary Material for: DOES BODY MASS INDEX IMPACT THE OUTCOMES OF PERITONEAL DIALYSIS PATIENTS? A SYSTEMATIC REVIEW AND META-ANALYSIS OF NON-RANDOMIZED TRIALS

Introduction: Body mass index (BMI) is a risk factor for adverse consequences in chronic kidney disease patients. However, its impact on patients undergoing peritoneal dialysis (PD) remains uncertain. We conducted a comprehensive systematic review and meta-analysis to assess the impact of baseline BMI on PD outcomes. Methods: All studies reporting outcomes of PD patients based on WHO-defined BMI groups were identified from PubMed, Embase, Scopus, and Cochrane Library databases up to March 30, 2025. Mortality, peritonitis rate, transfer to hemodialysis (HD), and technique failure were assessed. Results: 18 studies were included. Meta-analysis of crude data showed a significantly increased risk of mortality in obese patients, while meta-analysis of adjusted data showed significantly higher mortality rates in underweight patients as compared to those with normal BMI. Comparisons of overweight and normal BMI patients for mortality remained non-significant. We noted a significant increase in the risk of peritonitis in obese patients but not in overweight or underweight patients. None of the groups demonstrated significant results for transfer to HD. Descriptive analysis showed that technique failure may not be significantly different across BMI groups. Conclusions: Underweight PD patients seem to have a greater risk of mortality, while obese PD patients may have a higher risk of peritonitis. There seems to be no difference between the BMI groups for transfer to HD and technique failure. The high heterogeneity between studies limits strong conclusions.