P3618Underweight predicts greater risk of cardiac mortality post acute myocardial infarction

Abstract

Abstract Background Increased body mass index (BMI) is a well-established risk factor for cardiovascular disease, however, patients with elevated BMI comparing to low BMI seem to have better survival, a phenomenon reported as “obesity paradox” which remains as a controversy. We investigated the effect of BMI, including underweight, normoweight, overweight and obese, on cardiac mortality post acute myocardial infarction (AMI). Methods This analysis included 3562 AMI patients with documented BMI. The baseline characteristics including clinical and laboratory parameters were collected at hospital admission for AMI. Patients were classified into 4 groups based on BMI values: underweight (BMI <18.5), normoweight (BMI 18.5 to 24.9), overweight (BMI 25 to 29.9) and obese (BMI ≥30). Patients were followed up for a median of 1.9 years. The rate of cardiac death (primary endpoint) was compared among the 4 BMI groups. Cox proportional hazard models were used to adjust for potential confounders. Results Of 3562, 110 (3%) were underweight, 1579 (44%) were normoweight, 1493 (42%) were overweight, and 380 (11%) were obese. Compared to the normoweight group, subjects in overweight and obese groups were younger, more men, more hypertension, more likely to receive percutaneous coronary intervention (PCI), and had higher levels of glucose and lipids, but, lower level of N-terminal pro-brain natriuretic peptide (NTproBNP). Subjects in underweight group were older, more women, fewer diabetes, less likely to receive PCI, lower levels of glucose and lipids, but, higher level of NTproBNP and higher rates of left ventricular ejection fraction (LVEF)<50%. Cardiac death over 1.9 years occurred significantly more in the underweight group (30.0%, 10.6%, 7.0% and 5.0% among the 4 groups from underweight to obese, p<0.001 for trend, Figure 1). The Cox proportional hazard model revealed that underweight was an independent predictor of subsequent cardiac death (OR=2.58, 95% CI: 1.52–4.39, p<0.001). Multivariate analysis identified that older age, higher levels of cardiac troponin I (cTnI) and LVEF<50% were independently associated with increased risk of cardiac death. PCI significantly and independently protected AMI patients against cardiac death (OR=0.34, 95% CI: 0.23–0.49, p<0.001). Conclusions Patients who were underweight were at greater risk of cardiac death post AMI. In addition, older age, higher levels of cTnI, LVEF<50%, and not receiving PCI also independently predicted cardiac mortality post AMI. Acknowledgement/Funding Beijing Natural Science Foundation (No. 7194253);Scientific Research Common Program of Beijing Municipal Commission of Education (KM201910025017)