Abstract 207: Hospital Case Volume is Associated With Mortality in Patients Hospitalized With Subarachnoid Hemorrhage

Abstract

Background and Purpose: Prior studies have suggested hospital case volume may be associated with improved outcomes after SAH, but contemporary national data are limited. We hypothesized that high volume compared to low volume centers are associated with lower in-hospital mortality. Methods: Using the Get With The Guidelines-Stroke (GWTG-Stroke) registry, we analyzed patients with discharge diagnosis of SAH between April 2003 and March 2012. We assessed the association of annual SAH case volume with in-hospital mortality using multivariable logistic regression adjusting for relevant patient, hospital, and geographic characteristics. Results: Among 29,484 patients with SAH from 644 hospitals, the median annual case volume per hospital was 8.4 (25 th -75 th percentile 6.5-12.6) patients. Mean in-hospital mortality was 25.7% but was lower with increasing annual SAH volume (figure): 29.7% in quartile 1 (4-6.5 per year), 26.8% in quartile 2 (6.5-8.4 per year), 24.0% in quartile 3 (8.4-12.5 per year), and 22.2% om quartile 4 (>12.6 per year). Adjusting for patient (age, sex, race, medical history, stroke unit care, arriving time on or off hours) and hospital characteristics (bed size, location, teaching status, annual stroke volume, annual thrombolytic volume, and primary stroke center status), higher hospital SAH volume was independently associated with lower in-hospital mortality (adjusted odds ratio 0.80, 95% confidence intervals 0.68-0.95, highest quartile SAH volume hospitals compared with lowest quartile volume hospitals). Conclusions: In a large nationwide registry, we observed that patients treated at hospitals with higher volumes of SAH patients have lower in-hospital mortality, independent of patient and other hospital characteristics. Our data suggest that experienced centers may provide more optimized care for these patients.