Objective Obesity is paradoxically associated with enhanced survival in patients with established cardiovascular disease. We explored this paradox further by examining the influence of obesity on survival in patients with verified atherosclerotic heart disease.

Design and patients This retrospective registry based cohort study included all patients from the Western Denmark Heart Registry with coronary atherosclerosis confirmed by coronary angiography from January 2000 to December 2010. Patients were divided into eight groups according to body mass index (BMI) based on WHO BMI classification.

Setting Department of Cardiology, Copenhagen University Hospital Gentofte, Hellerup, Denmark.

Results The study included 37 573 patients (70.7% men) with a mean age of (66.3±11.1) years. During the 11 years of follow-up, 5866 (15.6%) patients died. Multivariable analysis confirmed that the risk of death was the lowest among the preobese patients (27.5≤BMI<30 kg/m²) with adjusted HR of 0.82 (95% CI 0.71 to 0.95; p=0.008) and increased with both low (BMI<18.50 kg/m²) and very high (BMI≥40 kg/m²) BMI, HR 2.04 (95% CI 1.63 to 2.57; p<0.001) and HR 1.35 (95% CI 1.05 to 1.72; p<0.01), respectively. Also the normal weight class I (18.5≤BMI<23 kg/m²) had a significant risk of mortality HR 1.28 (95% CI 1.13 to 1.45; p<0.001). Obese classes I and II did not differ from the reference group (23≤BMI<25 kg/m²).

Conclusions Overweight atherosclerotic heart disease patients have improved survival compared with normal weight patients. Underweight and severely obese patients have increased mortality. Our results lean more towards an overweight paradox than an obesity paradox.