Background: Prior studies have suggested hospital case volume may be associated with improved outcomes after subarachnoid hemorrhage (SAH), but contemporary national data are limited.
Objective: To assess the association between hospital case volume for SAH and 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 31,973 patients with SAH from 685 hospitals, the median annual case volume per hospital was 8.5 (25th-75th percentile 6.7-12.9) patients. Mean in-hospital mortality was 25.7% but was lower with increasing annual SAH volume: 29.5% in quartile 1 (range 4-6.6), 27.0% in quartile 2 (range 6.7-8.5), 24.1% in quartile 3 (range 8.5-12.7), and 22.1% in quartile 4 (range 12.9-94.5). Adjusting for patient and hospital characteristics, hospital SAH volume was independently associated with in-hospital mortality (adjusted odds ratio 0.79 for quartile 4 vs. 1, 95% confidence intervals 0.67-0.92). Quartile of SAH volume also was associated with length of stay but not with discharge home or independent ambulatory status.
Conclusion: 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 hospital characteristics. Our data suggest that experienced centers may provide more optimized care for SAH patients.
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