The Effect of Morbid Obesity on Subarachnoid Hemorrhage Prognosis in the United States

Objective The association between obesity and nontraumatic subarachnoid hemorrhage (SAH) patient outcome is unclear. The aim of this study was to determine the impact of morbid obesity (body mass index ≥40 kg/m²) on nontraumatic SAH outcomes. Methods Using the Nationwide Inpatient Sample, we identified hospitalized, nontraumatic SAH patients who received their diagnoses from 2008 to 2013 and tested the effect of obesity on their mortality and clinical outcomes. Odds ratios were estimated with a mixed effects linear logistic model with adjustment for hospital clustering. All statistical testing was 2-sided, with a significance level of 5%. Results Out of 224,561 discharged patients with a diagnosis of nontraumatic SAH, 4714 (2.10%) were defined as morbidly obese. Patients with morbid obesity were younger (54.3 ± 0.44 vs. 59.5 ± 0.08 years; P < 0.001) and had longer length of stay (LOS) (13 ± 0.46 vs. 11.5 ± 0.06 days; P = 0.002). Morbid obesity was associated with significantly higher hospital costs (P < 0.001) and charges (P < 0.001). The risk of acute respiratory failure was higher in morbidly obese patients (odds ratio [OR] 1.49, 95% confidence interval [CI]: 1.3–1.71, P < 0.001). In a multivariate analysis of hospital mortality, obesity had a negative impact on mortality (OR 0.83, 95% CI: 0.74–0.92, P < 0.001). Overall, in-hospital mortality was associated with age, morbid obesity, LOS, clipping and coiling, and acute respiratory failure but not the symptomatic vasospasm. Conclusions Morbid obesity is associated with increased LOS, hospital costs and charges and with acute respiratory failure. However, it is also associated with a decrease in hospital mortality.