Supplementary Material for: Encapsulating Peritoneal Sclerosis and Mortality Related to Infection in Patients on Combination Once-Weekly Hemodialysis with Peritoneal Dialysis

<b><i>Introduction:</i></b> Previous studies showed that the combination of peritoneal dialysis (PD) and once-weekly hemodialysis is associated with lower all-cause and cardiovascular mortality. This study aimed to compare the incidence of encapsulating peritoneal sclerosis (EPS) and infection-related mortality among those on combination therapy and those on PD alone. <b><i>Methods:</i></b> This prospective study on the Japanese Renal Data Registry included patients on PD from 2010 to 2014. Subjects were followed up until the end of 2015. Exposure of interest was combination therapy compared with PD alone. Patients who transitioned to combination therapy were matched with those on PD alone by propensity scores. Outcomes were EPS and infection-related mortality. Data were analyzed using Cox regression models. <b><i>Results:</i></b> Among the matched cohort, 608 and 869 patients were on combination therapy and on PD alone, respectively. Dialysate-to-plasma creatinine (D/P Cr) ratio decreased over time among those on combination therapy, while the ratio increased among those on PD alone (<i>p</i> = 0.01 by the mixed-effects model). During a median follow-up of 2.5 years, 33 experienced EPS and 55 died of infection. Combination therapy was associated with lower infection-related mortality (HR [95% CI]: 0.52 [0.28–0.95]) but not with EPS (HR: 1.21 [0.61–2.40]). Lower mortality was not limited to intra-abdominal infection but also observed for pulmonary infection. Sensitivity analyses considering the effects of dialysis facilities yielded similar results. <b><i>Conclusions:</i></b> Combination therapy was associated with lower infection-related mortality. It was also associated with a decline in the D/P Cr ratio over time but not with lower incidence of EPS during the short observation period.