Background: The prevalence of obesity is increasing worldwide. Obesity is also increasing in the chronic kidney disease (CKD) population. There are conflicting data on complications such as mortality, peritonitis, and technique proficiency of peritoneal dialysis (PD) in underweight and obese patients according to body mass index (BMI). We aimed to present the data in our region to the literature by comparing the residual renal function (RRF), peritonitis, technique proficiency, and mortality rates of the patients we grouped according to BMI.

Methods: The data of 404 patients who were started and followed up in our clinic between March 2005 and November 2021 were evaluated retrospectively. They were grouped as underweight, normal weight, overweight, and obese according to BMI. RRF, mortality, technique proficiency and peritonitis data of the groups were compared.

Results: Of the 404 patients, 44 were underweight, 199 were normal weight, 110 were overweight, and 55 were obese. No difference was found between the groups in the technique survey and in the time to first peritonitis with Kaplan-Meier analysis (respectively; p = 0.610, p = 0.445). Multivariate Cox regression analysis showed that BMI did not affect mortality (HR 1.196 [95% CI 0.722-1.981] (p = 0.488)).

Conclusion: In conclusion, we report that BMI has no effect on RRF, peritonitis, technique proficiency, and mortality in patients undergoing PD, and that mortality may depend on additional factors such as mean albumin, time to first peritonitis, and loss of RRF.