The Impact of the Body Mass Index on Outcome After Subarachnoid Hemorrhage

Abstract

Abstract BACKGROUND: Obesity is a risk factor for cardiovascular disease and associated with a poor outcome, especially for intensive care patients. However, recent studies have described favorable outcomes of obese patients after stroke, a phenomenon called the “obesity paradox.” OBJECTIVE: To assess the impact of the body mass index (BMI) on outcome after subarachnoid hemorrhage (SAH). METHODS: We analyzed the data for 741 SAH patients. A BMI greater than 25 kg/m2 was considered overweight and greater than 30 kg/m2 obese. The outcome according to the Glasgow Outcome Scale at discharge and after 6 months was assessed using logistic regression analysis. RESULTS: According to the BMI, 268 patients (36.2%) were overweight and 113 (15.2%) were obese. A favorable outcome (Glasgow Outcome Scale score >3) was achieved in 53.0% of overweight patients. In contrast, 61.4% of the 360 patients with a normal BMI had a favorable outcome (P = .021). However, in the multivariate analysis, only age (odds ratio [OR]: 1.051, 95% confidence interval [CI]: 1.04-1.07, P < .001), World Federation of Neurological Surgeons grade (OR: 2.095, 95% CI: 1.87-2.35, P < .001), occurrence of vasospasm (OR: 2.90, 95% CI: 1.94-4.34, P < .001), and aneurysm size larger than 12 mm (OR: 2.215, 95% CI: 1.20-4.10, P = .011) were independent predictors of outcome after 6 months. Of the 321 poor grade patients (World Federation of Neurological Surgeons score >3), 171 (53.3%) were overweight. Of these, 21.6% attained a favorable outcome compared with 35.3% of normal-weight patients (P = .006). CONCLUSION: Although many physicians anticipate a worse outcome for obese patients, in our study, the BMI was not an independent predictor of outcome. Based on the BMI, obesity seems to be negligible for outcome after SAH compared with the impact of SAH itself, the patient's age, occurrence of vasospasm, or aneurysm size.