Relation of Body Mass Index With Adverse Outcomes Among Patients With Atrial Fibrillation: A Meta-Analysis and Systematic Review.

BACKGROUND: Several studies have investigated the impact of body mass index (BMI) on the prognosis of atrial fibrillation, but the results remain controversial. We sought to estimate the association of BMI with atrial fibrillation-related outcomes.

METHODS AND RESULTS: We systematically searched the Cochrane Library, PubMed, and Elsevier databases for all studies reporting associations between BMI and atrial fibrillation-related outcomes. Relative risks (RRs) and 95% CIs were extracted and pooled. Nine studies with 49 364 participants were included. Underweight BMI was associated with an increased risk of stroke or systemic embolism (RR 1.67, 95% CI 1.12-2.49), all-cause mortaliity (RR 2.61, 95% CI 2.21-3.09), and cardiovascular death (RR 2.49, 95% CI 1.38-4.50). Nevertheless, the pooled RRs of overweight and obese patients were lower than those of normal-weight patients for stroke or systemic embolism (overweight: RR 0.91, 95% CI 0.80-1.04; obese: RR 0.84, 95% CI 0.72-0.98; grade 1 obesity: RR 0.89, 95% CI 0.71-1.11; grade 2 obesity: RR 0.64, 95% CI 0.45-0.91; grade 3 obesity: RR 0.82, 95% CI 0.54-1.25), all-cause death (overweight: RR 0.78, 95% CI 0.62-0.96; obese: RR 0.84, 95% CI 0.64-1.10; grade 1 obesity: RR 0.64, 95% CI 0.57-0.73; grade 2 obesity: RR 0.70, 95% CI 0.47-1.03; grade 3 obesity: RR 0.72, 95% CI 0.59-0.88), and cardiovascular death (overweight: RR 0.79, 95% CI 0.58-1.08; obese: RR 0.99, 95% CI 0.79-1.24).

CONCLUSIONS: Underweight BMI is associated with an increased risk of stroke or systemic embolism, cardiovascular death, and all-cause death in Asian patients with atrial fibrillation, whereas in all atrial fibrillation patients, overweight and obese BMI was not associated with increased risks of these outcomes.