Obesity Paradox and Long-term Cardiovascular Outcomes in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

INTRODUCTION: Obesity is a known modifiable risk factor for cardiovascular disease, and guidelines recommend maintaining a body mass index of 20–25 kg/m2 to reduce cardiovascular risk. However, several studies have reported that obese patients with acute coronary syndrome (ACS) may have better short- and long-term survival than their normal-weight counterparts-a phenomenon known as the “obesity paradox.” The effect of this paradox in ACS patients treated exclusively with percutaneous coronary intervention (PCI) remains unclear. This retrospective, two-center cohort study aimed to evaluate the impact of BMI on long-term mortality in ACS patients undergoing PCI, with a 3 years follow-up period.
METHODS: A total of 1,198 patients were categorized according to BMI as normal weight (n=321), overweight (n=753), and obese (n=124). Survival across BMI categories was evaluated using Kaplan-Meier analysis with log-rank testing. Univariate and multivariable Cox proportional hazards regression models (backward likelihood ratio method) were performed to identify predictors of long-term mortality.
RESULTS: In-hospital mortality was lowest among obese patients (2.2%) compared to overweight (2.8%) and normal-weight patients (7.4%) (χ2=12.448; p=0.002). Over a 3 years follow-up, mortality remained significantly lower in the obese (6.5%) and overweight (8.5%) groups compared with the normal-weight group (20.1%) (χ2=30.662; p<0.001). In multivariable analysis, smoking increased mortality risk by approximately 50% (Hazard ratio [HR]: 1.508; 95% confidence interval [CI]: 1.030–2.208; p=0.035), whereas obesity (HR: 0.297; 95% CI: 0.128–0.688; p=0.005) and overweight (HR: 0.404; 95% CI: 0.282–0.578; p<0.001) significantly reduced mortality risk.
DISCUSSION AND CONCLUSION: Although obesity remains a significant risk factor for the development of cardiovascular disease, the present findings support the existence of an obesity paradox among ACS patients treated with PCI. Obese and overweight patients demonstrated a 60–70% lower risk of long-term mortality compared with normal-weight patients. These results highlight the need for a more nuanced approach to risk stratification and treatment planning in this patient group.

Keywords: Acute coronary syndrome, body mass index, obesity paradox, survival.