The prognostic importance of worsening renal function during an acute myocardial infarction on long-term mortality

Background: Although an acute worsening in renal function (WRF) commonly occurs among patients hospitalized for acute myocardial infarction (AMI), its long-term prognostic significance is unknown. We examined predictors of WRF and its association with 4-year mortality. Methods: Acute myocardial infarction patients from the multicenter PREMIER study (N = 2,098) who survived to hospital discharge were followed for at least 4 years. Worsening in renal function was defined as an increase in creatinine during hospitalization of ≥0.3 mg/dL above the admission value. Correlates of WRF were determined with multivariable logistic regression models and used, along with other important clinical covariates, in Cox proportional hazards models to define the independent association between WRF and mortality. Results: Worsening in renal function was observed in 393 (18.7%) of AMI survivors. Diabetes, left ventricular systolic dysfunction, and a history of chronic kidney disease (documented history of renal failure with baseline creatinine >2.5 mg/dL) were independently associated with WRF. During 4-year follow-up, 386 (18.6%) patients died. Mortality was significantly higher in the WRF group (36.6% vs 14.4% in those without WRF, P < .001). After adjusting for other factors associated with WRF and long-term mortality, including baseline creatinine, WRF was independently associated with a higher risk of death (hazard ratio = 1.64, 95% CI 1.23-2.19). Conclusions: Worsening in renal function occurs in approximately 1 of 6 AMI survivors and is independently associated with an adverse long-term prognosis. Further studies on interventions to minimize WRF or to more aggressively treat patients developing WRF should be tested.