Association of obesity indices with in-hospital and 1-year mortality following acute coronary syndrome

Background/objectives: According to the “obesity paradox”, adults with obesity have a survival advantage following acute coronary syndrome, compared with those without obesity. Previous studies focused on peripheral obesity and whether this advantage is conferred by central obesity is unknown. The objective of this study was to describe the association of peripheral and central obesity indices with risk of in-hospital and 1-year mortality following acute coronary syndrome (ACS). Subjects/methods: Gulf COAST is a prospective ACS registry that enrolled 4044 patients age ≥18 years from January 2012 through January 2013, across 29 hospitals in four Middle Eastern countries. Associations of indices of peripheral obesity (body-mass index, [BMI]) and central obesity (waist circumference [WC] and waist-to-height ratio [WHtR]) with mortality following ACS were analyzed in logistic regression models (odds ratio, 95% CI) with and without adjustment for Global Registry of Acute Coronary Events risk score. Results: Of 3882 patients analyzed (mean age: 60 years; 33.3% women [n = 1294]), the prevalence of obesity was 34.5% (BMI ≥ 30.0 kg/m²), 72.2% (WC ≥ 94.0 cm [men] or ≥80.0 cm [women]) and 90.0% (WHtR ≥ 0.5). In adjusted models, deciles of obesity indices showed higher risk of mortality at extreme versus intermediate deciles (U-shaped). When defined by conventional cut-offs, peripheral obesity (BMI ≥ 30.0 versus 18.5–29.9 kg/m²) showed inverse association with risk of in-hospital mortality (0.64; 95% CI, 0.42–0.99; P = 0.04; central obesity showed trend toward reduced mortality). In contrast, for risk of 1-year mortality, all indices showed inverse association. Obesity, defined by presence of all three indices, versus nonobesity showed inverse association with risk of 1-year mortality (0.52; 95% CI, 0.35–0.75; P = 0.001). Results were similar among men and women. Conclusion: The degree of obesity paradox following ACS depends on the obesity index and follow-up time. Obesity indices may aid in risk stratification of mortality following ACS.