Incremental start and clinical outcomes in peritoneal dialysis: International results from PDOPPS

Background The impact of incremental peritoneal dialysis (PD) on outcomes is poorly understood, and there is a paucity of evidence informing best practices regarding the dialysis dose at the commencement of PD. This international prospective cohort study aimed to compare PD prescription practices at dialysis commencement and their subsequent association with clinical outcomes. Methods Adult patients who started PD for less than three months at the time of enrolment in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) between 1 January 2014 and 31 December 2017 were included. Patients were defined as initiating incremental PD if prescribed a total of <4 exchanges/day for continuous ambulatory peritoneal dialysis (CAPD) or, with dry days or having PD less than seven days per week for automated peritoneal dialysis (APD). All other prescriptions were considered standard PD. The primary outcome was the transfer to haemodialysis (HD). Secondary outcomes included peritonitis rate, time to first peritonitis and mortality. Logistic regression analysed PD uptake and the Cox proportional hazards regression model analysed HD transfer, peritonitis and patient survival. Results Overall, 1365 PD patients from 128 facilities across seven countries were included. Fewer individuals started on incremental PD than standard PD (37% vs 63%, p < 0.001). Higher incremental PD uptake was associated with receiving treatment in Japan (odds ratio [OR] 2.35, 95% CI 1.05–5.26, p = 0.04; ref: Canada), age >75 years (OR 1.51, 95% CI 1.02–2.24, p = 0.04), icodextrin use (OR 8.54, 95% CI 6.26–11.64, p < 0.001), lower serum creatinine concentration at PD start (OR 1.01, 95% CI 1.01–1.01, p = 0.007) and higher number of PD patients at a facility (OR 1.01, 95% CI 1.00–1.01, p = 0.02). Crude HD transfer rates for the incremental and standard PD groups were 0.14 (95% CI, 0.12–0.16) and 0.15 (95% CI, 0.13–0.17) per patient-year of follow-up, respectively (incidence rate ratio [IRR], 0.93; 95% CI, 0.75–1.15; p = 0.49). There was no significant difference in the hazard of HD transfer between the incremental and standard PD groups (hazard ratio [HR] 0.87, 95% CI 0.68–1.12, p = 0.29). There were also no differences between the two groups concerning peritonitis and mortality. Conclusions Incremental PD start was prescribed in approximately one-third of patients and, in low certainty evidence, was associated with comparable risks of HD transfer, peritonitis and death.