1185. Predictors of Increased Morbidity Following Aneurysmal Subarachnoid Hemorrhage Using National Inpatient Sample SAH Outcome Measure

Authors: Jonathan Christian Dallas; Campbell Liles, BS; Stephen Gannon, BS; Chevis Shannon, MBA, MPH, DrPH; Rohan Chitale, MD; Matthew Fusco, MD (Nashville, TN)


Aneurysmal subarachnoid hemorrhage (SAH) is associated with exceptionally high mortality. Morbidity related to SAH in those who survive is also significant, imposing great personal, socioeconomic, and infrastructural burden.  In this study, we use the novel National Inpatient Sample (NIS) SAH Outcome Measure (NIS-SOM) as an indicator of SAH-related morbidity in a large, diverse database (the National Inpatient Sample) to identify predictors of poor outcomes in patients with aneurysmal SAH.


Patients with aneurysmal SAH were identified using the 2012-2015 NIS. ICD9 codes selected for patients with (1) SAH (ICD9 diagnosis: 430) and (2) surgical aneurysm repair (clipping or endovascular; ICD9 procedure: 3951, 3952, 3972, or 3979). Patients with a zero-day length of stay, head trauma, or AVM/AVF were excluded. Independent variables included sociodemographics, hospital information, treatment type, neurovascular comorbidities index (NCI), and NIS-SAH Severity Score (NIS-SSS, a previously validated synthetic Hunt and Hess scale equivalent). Primary outcome was NIS-SOM. Missing data was imputed via the “multivariate imputation by chained equations” algorithm. Both univariate and multivariate logistic regression were used to identify predictors of poor NIS-SOM and calculate associated odds ratios (OR).


5355 unweighted patients were included, and the rate of poor outcomes (NIS-SOM) was 63.0%. Following multivariate regression, factors predictive of poor outcomes included increased age (OR=1.04/year, P<0.001), female sex (OR=1.18, P=0.027), hospital location in the Middle Atlantic (OR=2.04, P<0.001) or East North Central (OR=1.48, P=0.047) states, private non-profit hospital status (OR=1.28, P=0.009), increased NIS-SSS (OR=1.26/point, P<0.001), and increased NCI (OR=1.14/point, P<0.001). Factors predictive of good outcomes included aneurysm coiling (vs. clipping) (OR=0.62, P<0.001) and non-Medicare insurance (including Medicaid – OR=0.45, P<0.001, private – OR=0.51, P<0.001, and self-pay – OR=0.25, P<0.001).


Using NIS-SOM as a proxy for SAH-related morbidity, this study was able to identify several predictors of poor outcomes for survivors in this population.