Association of Renal Insufficiency with Treatment and Outcomes after Myocardial Infarction in Elderly Patients

BACKGROUND: Patients with end-stage renal disease are known to have decreased survival after myocardial infarction, but the association of less severe renal dysfunction with survival after myocardial infarction is unknown. OBJECTIVES: To determine how patients with renal insufficiency are treated during hospitalization for myocardial infarction and to determine the association of renal insufficiency with survival after myocardial infarction. DESIGN: Cohort study. SETTING: All nongovernment hospitals in the United States. PATIENTS: 130 099 elderly patients with myocardial infarction hospitalized between April 1994 and July 1995. MEASUREMENTS: Patients were categorized according to initial serum creatinine level: no renal insufficiency (creatinine level < 1.5 mg/dL <132 micromol/L; n = 82 455), mild renal insufficiency (creatinine level, 1.5 to 2.4 mg/dL 132 to 212 micromol/L; n = 36 756), or moderate renal insufficiency (creatinine level, 2.5 to 3.9 mg/dL 221 to 345 micromol/L; n = 10 888). Vital status up to 1 year after discharge was obtained from Social Security records. RESULTS: Compared with patients with no renal insufficiency, patients with moderate renal insufficiency were less likely to receive aspirin, beta-blockers, thrombolytic therapy, angiography, and angioplasty during hospitalization. One-year mortality was 24% in patients with no renal insufficiency, 46% in patients with mild renal insufficiency, and 66% in patients with moderate renal insufficiency (P < 0.001). After adjustment for patient and treatment characteristics, mild (hazard ratio, 1.68 95% CI, 1.63 to 1.73) and moderate (hazard ratio, 2.35 CI, 2.26 to 2.45) renal insufficiency were associated with substantially elevated risk for death during the first month of follow-up. This increased mortality risk continued until 6 months after myocardial infarction. CONCLUSIONS: Renal insufficiency was an independent risk factor for death in elderly patients after myocardial infarction. Targeted interventions may be needed to improve treatment for this high-risk population.