Peritoneal Dialysis Technique Survival: A Cohort Study

Abstract

Rationale & objective: Reasons for transfer from peritoneal dialysis (PD) to hemodialysis (HD) remain incompletely understood. Among incident and prevalent patients receiving PD, we evaluated the association of clinical factors, including prior treatment with HD, with PD technique survival.

Study design: Retrospective cohort study.

Setting & participants: Adults who initiated PD at a Dialysis Clinic, Inc (DCI) outpatient facility between January 1, 2010, and September 30, 2019.

Exposure: The primary exposure of interest was timing of PD start, categorized as PD-first, PD-early, or PD-late. Other covariates included demographics, clinical characteristics, and routine laboratory results.

Outcome: Modality switch from PD to HD sustained for more than 90 days.

Analytical approach: Multivariable Fine-Gray models with competing risks and time-varying covariates, stratified at 9 months to account for lack of proportionality.

Results: Among 5,224 patients who initiated PD at a DCI facility, 3,174 initiated dialysis with PD ("PD-first"), 942 transitioned from HD to PD within 90 days ("PD-early"), and 1,108 transitioned beyond 90 days ("PD-late"); 1,472 (28%) subsequently transferred from PD to HD. The PD-early and PD-late patients had a higher risk of transfer to HD as compared with PD-first patients (in the first 9 months: adjusted hazard ratio [AHR], 1.51 [95% CI, 1.17-1.96] and 2.41 [95% CI, 1.94-3.00], respectively; and after 9 months: AHR, 1.16 [95% CI, 0.99-1.35] and AHR, 1.43 [95% CI, 1.24-1.65], respectively). More peritonitis episodes, fewer home visits, lower serum albumin levels, lower residual kidney function, and lower peritoneal clearance calculated with weekly Kt/V were additional risk factors for PD-to-HD transfer.

Limitations: Missing data on dialysis adequacy and residual kidney function, confounded by short PD technique survival.

Conclusions: Initiating dialysis with PD is associated with greater PD technique survival, though many of those who initiate PD-late in their dialysis course still experience substantial time on PD. Peritonitis, lower serum albumin, and lower Kt/V are risk factors for PD-to-HD transfer that may be amenable to intervention.

Plain-language summary: Peritoneal dialysis (PD) is an important kidney replacement modality with several potential advantages compared with in-center hemodialysis (HD). However, a substantial number of patients transfer to in-center HD early on, without having experienced the quality-of-life and other benefits that come with sustained maintenance of PD. Using retrospective data from a midsize national dialysis provider, we found that initiating dialysis with PD is associated with longer maintenance of PD, compared with initiating dialysis with HD and a later switch to PD. However, many of those who initiate PD-late in their dialysis course still experience substantial time on PD. Peritonitis, lower serum albumin, and lower small protein removal are other risk factors for PD-to-HD transfer that may be amenable to intervention.

Keywords: End-stage kidney disease; end-stage renal disease; home dialysis; peritoneal dialysis.

Figure 1.. Study Cohort Diagram

Abbreviations: DCI: Dialysis Clinic, Inc.; HD: hemodialysis; PD: peritoneal dialysis

Figure 2.. Cumulative Incidence Function of PD-to-HD Transfer by Timing of PD Start

The cumulative probability of transfer from peritoneal dialysis (PD) to hemodialysis (HD) is expressed as the cumulative incidence function (CIF) of transfer with competing risks of death, withdrawal, kidney transplant or recovery of renal function. Censoring events were loss to follow-up, transfer to another dialysis provider, end of 5 years of follow-up, or study end date (December 31, 2019). Abbreviations: CIF: cumulative incidence function; HD: hemodialysis; PD: peritoneal dialysis