Abstract 19545: The Association Between Adiposity and Mortality in Patients with Coronary Artery Disease is Modified by Time

Abstract

Introduction: Obese Coronary Artery Disease (CAD) patients have improved short and intermediate term outcomes compared to those of normal weight. However excess mass may be associated with poor long-term outcomes. The objective of this study was to assess the association between weight and mortality in a population with CAD in different time frames.

Methods: We used the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH) database. Subjects were classified by BMI as normal weight (18.5 - 24.9kg/m2), overweight (25 - 29.9kg/m2), obese class I (30 - 34.9kg/m2), obese class II (35 - 39.9kg/m2), or obese class III (≥40 kg/m2). Mortality was considered over the entire follow-up, within 2 years of catheterization (short-term) or more than 2 years post-catheterization (long-term). Cox models were used to determine the association between weight and mortality. Models were adjusted for all clinical risk factors and initial treatment strategy.

Results: There were 45494 subjects with ≥ one vessel CAD (overweight: 41.9%, obese class I: 23.8%, obese class II: 7.8%, obese class III: 3.5%; 23.9% female; mean age 64.0 years). There were 7904 deaths over a median of 5.6 years of follow-up (61% after 2 years). In the complete follow-up period, compared to normal weight, the hazard ratio (HR) for mortality among overweight subjects was 0.84 (p<0.0001), obesity class I was 0.91 (p=0.004), obesity class II 0.98 (p=0.61), obesity class III 1.15 (p=0.038). There was a significant interaction between time and each weight class (p<0.0001). In short-term follow-up, the HR for overweight was 0.80 (p<0.001), for obese class I was 0.77 (p<0.001), for obese class II 0.80 (p=0.006) and for obese class III was 0.92 (p=0.434). With deaths in the first two years excluded, only overweight status was associated with reduced mortality, while obese class III was associated with increased mortality (HR 1.31 (95% CI 1.12, 1.54).

Conclusion: The association of adiposity with mortality in CAD patients varies by time, with the protective effect of excess weight diminishing over time. Conditions that decrease mass may result in early deaths.