title: Differential associations between body mass index and outcomes after elective adult cardiac surgery: a linked data cohort study.
abstract: This study assessed the relationships between body mass index (BMI) and different outcomes after adult cardiac surgery by linking detailed preoperative comorbidity data with the long-term mortality and morbidity outcomes of 2131 consecutive patients who had elective cardiac surgery at a major cardiac surgical hospital in Western Australia. Patients with a high BMI had more comorbidities and were more likely to have had coronary artery bypass grafting than valve surgery. A total of 143 patients (6.7%) died during a median follow-up period of 30 months. The major causes of death were congestive heart failure (25.9%), myocardial infarction (14.7%), infection (23.8%) and cancer (13.9%). BMI had no association with long-term mortality, after adjusting for important confounders including the Charlson Comorbidity Index. BMI had a relatively linear relationship with the risk of new-onset atrial fibrillation (odds ratio 1.05 per point increment, 95% confidence interval 1.03 to 1.05) and venous thromboembolism (odds ratio 1.20, 95% confidence interval 1.14 to 1.26). BMI was the second most important predictor after age and accounted for 22% of the variability in the risk of atrial fibrillation. BMI had an inverse relationship with the risk of requiring allogeneic blood transfusion, postoperative intra-aortic balloon pump, or surgical re-exploration. In summary, BMI had differential associations with different short- and long-term outcomes after elective adult cardiac surgery. After adjusting for important confounders including the presence of cancers, we did not observe any 'obesity paradox' and patients with a high BMI were not associated with an increased probability of long-term survival.
authors: Intensive Care Unit, Mount Hospital, Perth, Western Australia, Australia. kwok.ho@health.wa.gov.au
authors: K M
authors: KM
authors: Ho
authors: C
authors: C
authors: Bertenshaw
authors: S
authors: S
authors: Same
authors: M
authors: M
authors: Schneider
authors: K A
authors: KA
authors: Williams
authors: T
authors: T
authors: Godsell
authors: K
authors: K
authors: Hird
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology; D001803:Blood Transfusion; D015992:Body Mass Index; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D015331:Cohort Studies; D017558:Elective Surgical Procedures / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D054556:Venous Thromboembolism / Q000209:etiology
keywords: complications; haemorrhage; obesity; surgery; thrombosis