5072Obesity paradox outcomes after acute myocardial infarction in Japanese is due to optimal medical therapy in overweight patients

Abstract

Background: Although the counter-intuitive association between obesity and mortality has been termed the obesity paradox, the evidence in patients with coronary artery disease have been inconsistent, in contrast to those with con-gestive heart failure. The mechanisms for the paradox have yet to be clarified. We hypothesized that a different factor, in addition to the patient background, which concerned with obesity, may have an impact on adverse events in acute myocardial infarction (AMI) patients. Methods: To elucidate the impact of obesity, we analyzed data from the Japanese registry of acute Myocardial INfarction diagnosed by Universal dEfiniTion (J-MINUET). This was a prospective and multicenter registry consisting of 3,283 AMI patients, who were hospitalized within 48 hrs from onset, from July 2012 to March 2014. In total, 3,167 patients with known body parameters were stratified into 3 groups according to their degree of adiposity assessed by BMI (kg/m$sup$2$/sup$), utilizing WHO classification, under 18.5 kg/m$sup$2$/sup$ for Underweight, 18.5-24.9 kg/m$sup$2$/sup$ for Normal, and over 24.9 kg/m$sup$2$/sup$ for Overweight. Follow-up data was obtained for 3 years. The primary endpoint was a composite of all-cause death, non-fatal MI, non-fatal stroke, cardiac failure and urgent revascularization for unstable angina. The secondary endpoint was all-cause death. Results: There were 348 deaths (11.0%) during the 3-year follow up period. Regarding both the primary and secondary endpoints, we observed the obesity paradox which declines with increasing BMI (Figure). Ratio of female, older age, higher Killip classification, coexistence of atrial fibrillation, history of stroke, pe-ripheral artery disease, and multi-vessel disease were higher in Underweight pa-tients. Diabetes, hypertension, dyslipidemia, and current smoking were more frequent in Overweight patients. Overweight was an independent negative predictor for both endpoints. Kaplan-Meier analysis showed significant differences among the groups. Regarding medication at onset, usage rates of dual antiplatelet ther-apy (DAPT), calcium channel blocker (CCB), β-blockade (BB), and Nitrates were comparable among the groups, except for higher usage rate of RAAS blockades (25.8% vs. 30.5% vs. 33.9%, p=0.029) and Statins (15.7% vs. 24.1% vs. 24.0%, p=0.018) in Overweight patients. From the view point of medication at discharge, more optimal medical therapy (OMT) was observed in Overweight patients, as regards DAPT (70.8% vs. 76.1% vs. 76.2%), BB (66.5% vs. 68.0% vs. 69.9%), RAASs (75.3%. vs 78.9% vs. 81.2%), and Statins (74.2% vs. 86.7% vs. 90.2%). Achievement rates of OMT at discharge showed significant differences among the 3 groups, the ratio of prescribing all four types of medication was significantly higher in Overweight patients. (Figure) [Figure Presented] Conclusions: In Japanese AMI patients, a paradoxical protective effect of obesity was observed. This may be due, in part, to an OMT for those subjects.