Is the obesity paradox leading to a less stringent secondary prevention strategy in post-acute coronary syndrome patients?

Abstract Introduction Patients with acute coronary syndrome (ACS) are at very high risk of recurrent cardiovascular (CV) events. Despite being a major CV risk factor, obesity was associated with best survival in patients with ACS, the so-called "obesity paradox". It is uncertain if this finding is leading to a less stringent secondary prevention strategy in this group of patients, and whether it influences prognosis. Purpose To analyze the impact of obesity on outcomes after ACS and on other CV risk factor management. Methods Single-center, retrospective observational study that included all consecutive post-ACS patients enrolled in a phase 2 cardiac rehabilitation (CR) program in 2017, with a follow-up of 24 months. Patients were classified in 2 groups according to body mass index (BMI) at baseline: Group 1 (G1) were obese patients (BMI≥30 kg/m2), and Group 2 (G2) were non-obese patients (BMI<30kg/m2). Major adverse cardiovascular events (MACE) were defined as a composite of death, non-fatal ACS, non-fatal stroke, and unplanned revascularization. Results 198 patients were included (mean age of 60.3±10.7 years, 82% male) with a mean BMI of 27.7±4.2 kg/m2. Forty-seven patients (23.7%) had a BMI≥30 kg/m2. Patients in G1 were more likely to have hypertension (79% vs 55%; p=0.003) and diabetes (36% vs 20%; p=0.022). CR program was associated with smoking cessation, significant BMI (G1: -0.69 (95%CI: -0.40 to -0.10); G2: -0.39 (95%CI: -0.20 to -0.57) and LDL-Cholesterol (LDL-C) reduction (G1: -38 (95%CI: -25 to -50); G2: -29 (95%CI: -22 to -36), and functional capacity improvement (G1: +1.2 METs (95%CI: +0.9 to +1.5); G2: +1.1 METs (95%CI: +1.0 to +1.4) in both groups at 3 months, with similar magnitude of improvement. At 24 months, BMI had returned to baseline values in both groups, while the improvement in smoking status, LDL-C and functional capacity persisted. At 24 months, MACE occurrence was numerically increased in obese group (G1: 26.1% vs. G2: 17.2%, p=0.182), with a statistically significant higher incidence of non-fatal recurrent ACS in G1 (17% vs. 7.3%, p=0.048). Conclusions ACS patients with obesity have worse prognosis, despite the similar improvement in CV risk profile. Our data also suggests that, despite the short-term improvement in BMI, current treatment strategies are not effective at achieving a persistent weight control over 24-months.