Atrial fibrillation in chronic dialysis patients in the United States: risk factors for hospitalization and mortality

Abstract

Background: The incidence and risk factors for hospitalized atrial fibrillation have not been previously assessed in a national population of dialysis patients.

Methods: We analyzed the United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Study (DMMS) Wave II in a historical cohort study of hospitalized atrial fibrillation. Data from 3374 patients who started dialysis in 1996 with valid follow-up times were available for analysis, censored at the time of renal transplantation and followed until November 2000. Cox Regression analysis was used to model factors associated with time to first hospitalization for atrial fibrillation (ICD9 code 427.31x) adjusted for comorbidities, demographic factors, baseline laboratory values, blood pressures, dialysis modality, and cardioprotective medications.

Results: The incidence density of atrial fibrillation was 12.5/1000 person years. Factors associated with atrial fibrillation were older age (> or = 71 years vs. <48 years), extremes (both high and low) of pre-dialysis systolic blood pressure, dialysis modality (hemodialysis vs. peritoneal dialysis), and digoxin use. Baseline use of coumadin was associated with reduced mortality in patients later hospitalized for atrial fibrillation.

Conclusions: Dialysis patients had a high incidence of atrial fibrillation. This risk was largely segregated among those with established risk factors for atrial fibrillation, and hemodialysis patients. Use of coumadin was associated with improved survival among patients later hospitalized for atrial fibrillation.

Figure 1

Time to Hospitalization for Atrial Fibrillation by Quartile of pre-dialysis systolic blood pressure (mm Hg), (1 = <130, 2 = 131–146, 3 = 147–162, 4 = >162). As shown, patients at the extremes of predialysis systolic blood pressure had the greatest risk of subsequent hospitalizations for atrial fibrillation.

Figure 2

Mortality after hospitalization for Atrial Fibrillation, limited to patients hospitalized for atrial fibrillation (M = 123), stratified by patients with baseline coumadin use (COUM) vs. no baseline coumadin use (NO COUM), P < 0.001 by Log Rank Test.