Effect of Low Body Mass Index on the Clinical Outcomes of Japanese Patients With Acute Myocardial Infarction - Results From the Prospective Japan Acute Myocardial Infarction Registry (JAMIR).

Abstract

Acute myocardial infarction (AMI) patients with low body mass index (BMI) exhibit worse clinical outcomes than obese patients; however, to our knowledge, no prospective, nationwide study has assessed the effect of BMI on the clinical outcomes of AMI patients.Methods and Results:In this multi-center, prospective, nationwide Japanese trial, 2,373 AMI patients who underwent emergent percutaneous coronary intervention within 12 h of onset from the Japanese AMI Registry (JAMIR) were identified. Patients were divided into the following 4 groups based on their BMI at admission: Q1 group (BMI <18.5 kg/m2, n=133), Q2 group (18.5≤BMI<25.0 kg/m2, n=1,424), Q3 group (25.0≤BMI<30.0 kg/m2, n=672), and Q4 group (30.0 kg/m2≤BMI, n=144). The primary endpoint was all-cause death, and the secondary endpoint was a composite of cardiovascular death, non-fatal myocardial infarction (MI), and non-fatal stroke. The median follow-up period was 358 days. Q1 patients were older and had lower prevalence of coronary risk factors. Q1 patients also had higher all-cause mortality and higher incidence of secondary endpoints than normal-weight or obese AMI patients. Multivariate analysis showed that low BMI (Q1 group) was an independent predictor for primary endpoint. AMI patients with low BMI had fewer coronary risk factors but worse clinical outcomes than normal-weight or obese patients.