Impact of Anemia on Long-Term Outcomes and Mortality in ST-Segment Elevation Myocardial Infarction Patients: A SEMI-CI Cohort Study

Abstract

Background: This study aimed to evaluate the effect of hemoglobin (Hb) levels on 3-year clinical outcomes and long-term cardiovascular-related mortality in MI patients. Methods: This study is a secondary study of the ST Elevation Myocardial Infarction Cohort Study (SEMI-CI) in Isfahan, Iran, that included 844 STEMI patients. The Hb level and other clinical and biochemical data during hospitalization were recorded at admission and also for 3 years annually. Cox regression analyses (univariate and multivariate) were performed to identify hazard ratios for CVD events. Results: The prevalence of anemia was 16.7 in our population. Anemia was associated with an increased risk of the composite event (HR: 2.38, 95 CI: 1.77-3.19), mortality (HR: 2.91, 95 CI: 2.03-4.15), and unstable angina (HR: 2.22, 95 CI: 1.07-4.58) during a 3-year follow-up. After adjusting factors including smoking, diabetes, hypercholesterolemia, atrial fibrillation, treated hypertension, and BMI, anemia was only associated with an increased risk of the composite event and mortality. The 3-year cardiovascular survival curve showed better results in the nonanemic group (P value < 0.0001). Conclusions: Anemia was associated with a higher prevalence of 3-year mortality in STEMI patients, especially in the first year. In addition, there were associations between anemia and some CVD events in long-term follow-ups such as composite CVD events and unstable angina in our population.