Trends in Outcomes Among Patient Initiating Peritoneal Dialysis in the United States, 2009-2018.

RATIONALE & OBJECTIVE Peritoneal dialysis (PD) use has increased since 2009. We sought to evaluate how historic disparities in outcomes across different demographic groups have changed over time. STUDY DESIGN Retrospective cohort study. SETTING & PARTICIPANTS Patients initiating PD from 2009 to 2018 in the US represented in the US Renal Data Systems (USRDS). EXPOSURES Patient age group, race/ethnicity, urban or rural residence, obesity status, and level of neighborhood deprivation. OUTCOMES Mortality and conversion to in-center hemodialysis (HD) in one and two years following dialysis initiation. ANALYTICAL APPROACH The cumulative incidence of events was estimated for each yearly cohort. Temporal trends were evaluated using Cox proportional hazards models (mortality) and Fine-Gray models (conversion to HD). RESULTS The study included 101,640 incident PD patients, of whom 38.1% were aged ≥65 years, and 57.5% were White. The overall mortality one year after PD initiation decreased from 11.0% in 2009 to 8.4% in 2018, and the hazard decreased by 3% per two study years(hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.96-0.99). The probability of conversion to in-center HD one year after PD initiation decreased from 17.8% in 2009 to 15.1% in 2018, and the hazard decreased by 2% per two study years (HR 0.98, 95% CI, 0.97-1.00). Patients over 75 did not experience lower conversion to HD over time (HR 1.02, 95% CI 0.99-1.05, p for age interaction= 0.02). Overall, the hazard of conversion to HD in the two years following PD initiation did not improve. Hazards of mortality and conversion to HD changed similarly, regardless of urban or rural residence, race/ethnicity, obesity, or level of neighborhood deprivation. LIMITATIONS Incomplete data on medical comorbidities. CONCLUSIONS The rate of mortality improved for incident PD patients regardless of patient demographic factors over the period 2009 to 2020. Hazards of conversion to in-center HD improved less and attenuated with longer follow-up.