Relationship of body mass index to clinical outcomes after percutaneous coronary intervention

Abstract

Background: Elevated body mass index (BMI) demonstrates lower all-cause and cardiovascular mortalities compared with normal-weight or lean patients in chronic diseases. This study investigated relationships between BMI and clinical outcomes following percutaneous coronary intervention (PCI) in coronary artery disease (CAD) patients, together with the sex-specific impacts of BMI on mortality.

Methods: We reviewed 1104 CAD patients who underwent PCI between 2006 and 2015. Patients were divided by BMI into three groups: lean, <18.5 kg/m² ; normal, 18.5-24.9 kg/m² ; and overweight/obese, ≥25 kg/m² . The primary endpoint was all-cause mortality, and the secondary endpoint was 3-point major adverse cardiovascular events (MACE).

Results: Kaplan-Meier survival analysis demonstrated risks of all-cause death, and 3-point MACE were higher in lean patients compared with normal-weight and overweight/obese subjects (log-rank p < .001). Cox proportional hazard modelling showed overweight/obese was significantly associated with all-cause death (hazard ratio (HR) 0.68, 95% confidence interval (CI) 0.48-0.95; p = .03), and lean was significantly associated with 3-point MACE (HR 2.02, 95% CI 1.15-3.53; p = .01). Cox proportional hazard analysis with restricted cubic spline showed non-linear associations between BMI and both all-cause mortality and 3-point MACE (p for effect = .002 and = .003, respectively). No significant interaction was evident between sex and BMI for all-cause mortality (p for interaction = .104) or 3-point MACE (p for interaction =0.122).

Conclusions: Lean category was associated with adverse outcomes among CAD patients. An obesity paradox regarding the independent association of elevated BMI with reduced mortality after PCI is evident in both males and females.

Keywords: all-cause mortality; body mass index; cachexia; coronary artery disease; lean; major adverse cardiac and cerebral event; obesity; sex; syntax score.