Analysis of the obesity paradoxic according to the sex: relation between body mass index and mortality in the first year after an acute coronary syndrome

Introduction: Obesity is considered a global epidemic, with alarming prevalence and incidence. The aim was to investigate the relationship between obesity (in terms of body mass index, BMI) and the prognosis of patients with acute coronary syndrome (ACS). Methods: We studied a total of 3436 consecutive ACS patients. This cohort was divided into 4 groups according to BMI: normal weight (BMI <25 kg/m2), overweight (BMI 25 to 29.9 kg/m2), obesity grade I (BMI 30 to 34.9 kg/m2) and grade II obesity (BMI 35 to 39.9 kg/m2. Patients with BMI <18.5 kg/m2 (underweight) (n = 19) or ≥ 40 kg/m2 (morbid obesity) (n = 17) were excluded from analysis since the low number of patients belonging to each group (it did not allow precise analysis or comparison). The primary end-point was 1-year mortality. Results: After 1 year of follow up, 189 patients (5.5%) died. Patients with normal weight compared with those with BMI >25 kg/m2 had higher mortality (8.0% vs 4.9%, P = 0.002), in both NSTEMI (8.5% vs. 5, 7, p = 0.024) and STEMI (6.8% vs 3.2%, p = 0.017). For the different BMI groups, patients with BMI between 30 and 35 kg/m2 were those with lower mortality, with statistically significant differences compared to patients with normal weight (3.2% vs. 8.0%, p <0.001). These differences remained statistically significant only in men, not in women (Figure). After adjusting for the predictors of one year mortality in univariate analysis, BMI was inversely associated with mortality in men (HR 0.950, 95% CI 0.903 to 1.000, p = 0.049), but not in women (HR 0.996, 95% CI 0.936 to 1.059, p = 0.894). ![Figure][1] Figure 1 Conclusion: The main clinical finding of our study, based on its clinical implication, is that BMI was inversely associated with mortality in the first year after ACS in men, but not in women. [1]: pending:yes