Predictors of survival in dialysis patients in the United States after acute myocardial infarction.

Abstract

Background: Acute myocardial infarction (AMI) in dialysis patients continues to be associated with poor survival. This study aimed to identify predictors of survival in dialysis patients prior to AMI and to examine the association between survival and different revascularization techniques. Methods and Results: 3,049 US prevalent dialysis patients hospitalized for AMI between April 1, 1998, and June 30, 2000, were identified by cross-matching the United States Renal Data System (USRDS) database and the Third National Registry of Myocardial Infarction (NRMI 3). Of the 3011 data abstraction forms, 1,696 were suitable for analysis. Mean age was 67.0 ±11.9 years and average dialysis duration was 2.8 ± 3.2 years. Of the cohort, 69% were white and 47% were women. Diabetes and dysrhythmia were present in 72.5% and 65.5%, respectively. These two conditions were used for patient stratification. At 1 year post-AMI, 62% of the cohort died. The impact of independent predictors on survival was examined in a Cox proportional hazards model. Beta blockers use was associated with improved 1-year all-cause mortality (hazard ratio [HR] 0.8, P = 0.003). Compared with dialysis via catheter, fistula use was associated with favorable outcome (HR = 0.75, P = 0.0047), as was graft use (HR = 0.8 , P = 0.0054). Compared with predialysis systolic blood pressure 120-179 mmHg, values < 120 mmHg were more hazardous (HR =1.46, P ≤ 0.0001) and ≥ 180 mmHg less hazardous (HR = 0.7, P = 0.004). Coronary artery bypass graft surgery (CABG) and percutaneous coronary intervention (PCI) within 30 days of AMI were examined in time-dependent Cox models. CABG was not significantly associated with improved survival (HR = 0.87, P = 0.35), while PCI showed a strong protective association (HR = 0.67, P = 0.0005). Conclusion: Beta Blocker use prior to AMI, vascular access with fistula or graft and PCI within 30 days of AMI are associated with improved one year survival in dialysis patients. Optimal target blood pressure in dialysis patients remains controversial. Validation of these observational data by randomized clinical trials is needed as the impact of selection bias and unknown confounders may not be accounted for in our study.