Left ventricular ejection fraction and adjudicated, cause-specific hospitalizations after myocardial infarction complicated by heart failure or left ventricular dysfunction

Background Reduced left ventricular ejection fraction (LVEF) after acute myocardial infarction (MI) increases risk of cardiovascular (CV) hospitalizations, but evidence regarding its association with non-CV outcome is scarce. We investigated the association between LVEF and adjudicated cause-specific hospitalizations following MI complicated with low LVEF or overt heart failure (HF). Methods In an individual patient data meta-analysis of 19,740 patients from 3 large randomized trials, Fine and Gray competing risk modeling was performed to study the association between LVEF and hospitalization types. Results The most common cause of hospitalization was non-CV (n = 2,368 for HF, n = 1,554 for MI, and n = 3,703 for non-CV). All types of hospitalizations significantly increased with decreasing LVEF. The absolute risk increase associated with LVEF ≪25% (vs LVEF ≫35%) was 15.5% (95% CI 13.4-17.5) for HF, 4.7% (95% CI 3.0-6.4) for MI, and 10.4% (95% CI 8.0-12.8) for non-CV hospitalization. On a relative scale, after adjusting for confounders, each 5-point decrease in LVEF was associated with an increased risk of HF (hazard ratio [HR] 1.15, 95% CI 1.12-1.18), MI (HR 1.06, 95% CI 1.03-1.10), and non-CV hospitalization (HR 1.03, 95% CI 1.01-1.05). Conclusions In a high-risk population with complicated acute MI, the absolute risk increase in non-CV hospitalizations associated with LVEF ≪25% was two thirds of the absolute risk increase in HF hospitalizations and twice the absolute risk increase in MI hospitalizations. LVEF was an independent predictor of all types of hospitalization and appears as an integrative marker of sicker patient status.