Effect of obesity on short- and long-term mortality postcoronary revascularization: a meta-analysis.

OBJECTIVE: Overweight and obesity are often assumed to be risk factors for postprocedural mortality in patients with coronary artery disease (CAD). However, recent studies have described an "obesity paradox" -- a neutral or beneficial association between obesity and mortality postcoronary revascularization. We reviewed the effect of overweight and obesity systematically on short- and long-term all-cause mortality post-coronary artery bypass grafting (CABG) and post-percutaneous coronary intervention (PCI).
METHODS: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Scopus, and Web of Science to identify cohort, case control, and randomized controlled studies evaluating the effect of obesity on in-hospital/short-term (within 30 days) and long-term (up to 5 years) mortality. Full-text, published articles reporting all-cause mortality between individuals with and without elevated BMI were included. Two reviewers independently assessed studies for inclusion and performed data extraction.
RESULTS: Twenty-two cohort publications were identified, reporting results in ten post-PCI and twelve post-CABG populations. Compared to individuals with non-elevated BMI levels, obese patients undergoing PCI had lower short- (odds ratio (OR) 0.63; 95% confidence interval (CI) 0.54-0.73) and long-term mortality (OR 0.65; 95% CI 0.51-0.83). Post-CABG, obese patients had lower short-term (OR 0.63; 95% CI 0.56-0.71) and similar long-term (OR 0.88; 95% CI 0.60-1.29) mortality risk compared to normal weight individuals. Results were similar in overweight patients for both procedures.
CONCLUSIONS: Compared to non-obese individuals, overweight and obese patients have similar or lower short- and long-term mortality rates postcoronary revascularization. Further research is needed to confirm the validity of these findings and delineate potential underlying mechanisms.