Dialysis Modality and Incident Atrial Fibrillation in Older Patients With ESRD

Rationale & Objective: Atrial fibrillation (AF) is common in patients with kidney failure treated by maintenance dialysis. Whether the incidence of AF differs between patients receiving hemodialysis and peritoneal dialysis is uncertain. Study Design: Retrospective cohort study. Setting & Participants: Using the US Renal Data System, we identified older patients (>= 67 years) with Medicare Parts A and B who initiated dialysis therapy (1996-2011) without a diagnosis of AF during the prior 2 years. Exposure: Dialysis modality at incident end-stage renal disease (ESRD) and maintained for at least 90 days. Outcome: Patients were followed up for 36 months or less for a new diagnosis of AF. Analytical Approach: Time-to-event analysis using multivariable Cox proportional hazards regression to estimate cause-specific HRs while censoring at modality switch, kidney transplantation, or death. Results: Overall, 271,722 older patients were eligible; 17,487 (6.9%) were treated with peritoneal dialysis, and 254,235 (93.1%), with hemodialysis, at the onset of ESRD. During 406,225 person-years of follow-up, 69,705 patients had AF newly diagnosed. Because the proportionality assumption was violated, we introduced an interaction term between time (first 90 days vs thereafter) and modality. The AF incidence during the first 90 days was 187/1,000 person-years on peritoneal dialysis therapy and 372/1,000 person-years on hemodialysis therapy. Patients on peritoneal dialysis therapy had an adjusted 39% (95% CI, 34%-43%) lower incidence of AF than those on hemodialysis therapy. From day 91 onward, AF incidence was similar to 140/1,000 person-years with no major difference between modalities. Limitations: Residual confounding from unobserved differences between exposure groups; ascertainment of AF from billing claims; study of first modality may not generalize to patients switching modalities; uncertain generalizability to younger patients. Conclusions: Although patients initiating dialysis therapy using peritoneal dialysis had a lower AF incidence during the first 90 days of ESRD, there was no major difference in AF incidence thereafter. The value of interventions to reduce the early excess AF risk in patients receiving hemodialysis may warrant further study.