The influence of optimal medical treatment on the ‘obesity paradox’, body mass index and long-term mortality in patients treated with percutaneous coronary intervention: a prospective cohort study

Abstract

OBJECTIVE: To assess whether the obesity paradox persists in the long term and to study the effect of optimal medical treatment on this phenomenon. DESIGN: A retrospective cohort study. SETTING: A tertiary care centre in Rotterdam. PARTICIPANTS: From January 2000 to December 2005, 6332 patients undergoing percutaneous coronary intervention for coronary artery disease were categorised into underweight (body mass index (BMI)<18.5), normal (18.5-24.9), overweight (25-29.9) and obese (>30). PRIMARY OUTCOME MEASURE: Mortality. SECONDARY OUTCOME MEASURES: Cardiac death and non-fatal myocardial infarction. RESULTS: Optimal medical treatment was more common in obese patients as compared with normal weight patients (85% vs 76%; p<0.001). At a mean of 6.1 years, overweight and obese patients had a lower risk of all-cause mortality (HR: 0.75, 95% CI 0.66 to 0.86 and HR: 0.72, 95% CI 0.60 to 0.87, respectively). After adjusting for OMT in the multivariate analysis, BMI did not remain an independent predictor of long-term mortality (HR: 0.90, 95% CI 0.72 to 1.12 and HR: 1.07, 95% CI: 0.80 to 1.43, respectively). CONCLUSION: BMI is inversely related to long-term mortality in patients treated with percutaneous coronary intervention. Patients with a normal BMI are on suboptimal medical treatment when compared with those with a high BMI. A more optimal medical treatment in the obese group may explain the observed improved outcome in these patients.