The Impact of Body Mass Index on the Mortality of Myocardial Infarction Patients With Nonobstructive Coronary Arteries

Objectives Myocardial infarction without significant stenosis or occlusion of the coronary arteries carries a high risk of recurrent major adverse cardiovascular events and poor prognosis. This study aimed to investigate the association between body mass index and outcomes in patients with a suspected myocardial infarction with nonobstructive coronary artery disease (MINOCA). Methods Patients were recruited at Bergmannsheil University Hospital from January 2010 to April 2021. The primary outcomes were in‐hospital and long‐term mortality. Secondary outcomes consisted of adverse events during hospitalization and during follow‐up. Results A total of 373 patients were included in the study, with a mean follow‐up time of 6.2 years. The patients were divided into different BMI groups: < 25 kg/m² ( n = 121), 25−30 kg/m² ( n = 140), and > 30 kg/m² ( n = 112). In‐hospital mortality was 1.7% versus 2.1% versus 4.5% ( p = 0.368). However, long‐term mortality tended to be higher in the < 25 kg/m² group compared to the 25−30 and > 30 kg/m² groups (log‐rank p = 0.067). Subgroup analysis using Kaplan−Meier analysis showed a higher rate of cardiac cause of death in the < 25 kg/m² group compared to the 25−30 and > 30 kg/m² groups: 5.7% versus 1.1% versus 0.0% (log‐rank p = 0.042). No significant differences were observed in other adverse events between the different BMI groups during hospitalization and long‐term follow‐up. Conclusions Patients with a BMI < 25 kg/m² who experience a suspected myocardial infarction without significant coronary artery disease may have higher all‐cause mortality and cardiovascular cause of death. However, further data are needed to confirm these findings.