Association between the use of exchange devices for peritoneal dialysis fluids and peritonitis incidence: A nationwide cohort study

Background: The use of exchange devices for peritoneal dialysis (PD) fluids is a common practice in Japan. Evidence on the effectiveness of exchange devices in preventing PD-related peritonitis is scarce. We evaluated the association between the use of exchange devices for PD fluids and peritonitis incidence. Methods: We retrospectively enrolled 3845 patients, aged >= 20 years, receiving PD for >= 3 months, with available data on the exchange procedure for PD fluids and peritonitis incidence that was obtained from the Japan Renal Data Registry, a nationwide annual survey. The patients were grouped according to whether the manual or device PD fluid exchange method was used. The onset of peritonitis was defined as a leukocyte count of >100/mu L (neutrophils >= 50%) in PD effluents. We applied quasi-Poisson regression analyses to estimate the incidence rate ratio (IRR). Age, sex, PD vintage, body mass index, automated PD use, residual kidney function, comorbidities, haemoglobin and serum albumin were adjusted as potential confounders. Results: Older age, automated PD use, diabetes as comorbidity and lower haemoglobin levels were associated with the use of exchange devices for PD fluids. Patients using devices for PD fluid exchange (69.2%) had an increased risk of peritonitis of 37% (IRR: 1.37, 95% confidence interval (CI): 1.07-1.75) and 28% (IRR: 1.28, 95% CI: 1.00-1.63) in the crude and multivariate adjustment models, respectively. Conclusions: The use of exchange devices for PD fluids and peritonitis incidence showed no favourable association. There may remain possible residual confounding by indication.