Atrial fibrillation is the most common complication after coronary artery bypass grafting (CABG) surgery. Patients with large body size undergoing CABG surgery have been growing due to the ongoing epidemic of obesity. Primary studies have showed conflicting results regarding whether obesity increases the risk of postoperative atrial fibrillation (POAF). It is also remains undefined how obstructive sleep apnea (OSA) may affect the relationship between obesity and POAF.
We collected data on 9,993 consecutive patients without preoperative atrial fibrillation who underwent isolated CABG surgery during July 1, 2000 to June 30, 2007. The incidence of new-onset POAF and factors having potential influence on POAF were stratified by body mass index (BMI=kg/m2.).
2,305 (23.1%) patients had normal body habitus (BMI 19–24), 113 (1.1%) patients were underweight (BMI<19), 3,942 (39.4%) patients were overweight (BMI 25–29), 3,199 (32%) were obese (BMI 30–39), and 434 (4.3%) patients were severely obese (BMI≥40). As BMI increased, patients were significantly younger but more likely to have hypertension, diabetes, hypercholesteromia, and family history of cardiovascular disease. The prevalence of OSA increased with BMI increasing except normal BMI group presented the lowest prevalence. The incidence of new-onset POAF presented in U-shape with highest in the underweight (32%, P=0.39) and severely obese group (32%, P=0.47), lowest in the overweight group (26%, P<0.01), and significantly lower in the obese group (27%, P=0.03) compared with normal-weight patients (30%). In multivariable models adjusted for covariate risk factors including age and OSA, obese patients had 29% increased risk (OR 1.29, 95%CI 1.13–1.49, P<0.01) and severely obese patients had 115% increased risk (OR 2.15, 95%CI 1.66–2.77, P<0.01) for developing POAF compared with patients with normal BMI. OSA was not associated with increased POAF (OR 0.92, 95%CI 0.73–1.17, P=0.52).
After adjusting for covariate risk factors including age and obstructive sleep apnea, obesity (BMI≥30) still remains a significantly independent predictor of POAF.
Obesity is independently associated with POAF. There is no association between OSA and POAF.
Xiumei Sun, No Financial Disclosure Information; No Product/Research Disclosure Information