Sex-specific differences in mortality and the obesity paradox of patients with myocardial infarction ages >70 y

Objectives: Recent studies suggest an obesity survival paradox in patients with acute myocardial infarction (MI). The aim of this study was to investigate the in-hospital mortality of patients aged ≥70 y with acute MI relative to sex and obesity.

Methods: We selected patients ≥70 y of age with a diagnosis of acute MI based on the International Classification of Diseases (ICD) code I21 in the nationwide database of the Federal Statistical Office of Germany in 2014. We stratified the patients for sex and obesity versus nonobesity, and obesity classes I, II, and III. We compared the in-hospital mortality of these groups.

Results: In 2014, 122 607 patients ≥70 y of age were diagnosed with acute MI in Germany. Among these inpatients 14 342 (11.7%) died during their in-hospital stay. The calculated incidence was 938.46 per 100 000 citizens. Overall, 7874 MI patients (6.4%) had an additional coded diagnosis of obesity; 513 of these patients (6.5%) died while in the hospital. The number of MI events was higher in men than in women (56.2 versus 43.8%), whereas mortality rate of the women exceeded that of the men (12.7 versus 10.9%). Obesity mitigated sex differences in mortality after MI. Overall mortality after acute MI was distinctly lower in all obesity classes relative to MI patients without coded obesity. Relative mortality risk was 0.45, 0.62, and 0.75 in obesity classes I, II, and III, respectively. The present results point to a pronounced obesity paradox in women.

Conclusions: Obesity is associated with lower in-hospital mortality in patients ≥70 y with MI relative to MI patients without coded obesity. Although women showed higher in-hospital mortality, sex differences were significantly attenuated by obesity. Women showed a pronounced obesity paradox in the higher obesity classes.