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Hospital Case Volume Is Associated With Mortality in Patients Hospitalized With Subarachnoid Hemorrhage

Prabhakaran, Shyam MD, MS*; Fonarow, Gregg C. MD; Smith, Eric E. MD, MPH§; Liang, Li PhD; Xian, Ying MD, PhD; Neely, Megan PhD; Peterson, Eric D. MD, MPH; Schwamm, Lee H. MD

doi: 10.1227/NEU.0000000000000475
Research-Human-Clinical Studies
Press Release

BACKGROUND: Prior studies have suggested that 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 registry, we analyzed patients with a discharge diagnosis of SAH between April 2003 and March 2012. We assessed the association of annual SAH case volume with in-hospital mortality by 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 interval, 0.67-0.92). The 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.

ABBREVIATIONS: GWTG, Get With The Guidelines

SAH, subarachnoid hemorrhage

LOS, length of stay

IQR, interquartile range

NIHSS, National Institutes of Health Stroke Scale

CI, confidence interval

CSC, Comprehensive Stroke Center

*Department of Neurology, Northwestern University, Chicago, Illinois;

Ahmanson-UCLA Cardiomyopathy Center, Los Angeles, California;

§Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada;

Duke Clinical Research Institute, Durham, North Carolina; and

Division of Neurology, Massachusetts General Hospital, Boston, Massachusetts

Correspondence: Shyam Prabhakaran, MD, MS, Northwestern University-Feinberg School of Medicine, Department of Neurology, 710 N Lake Shore Dr, Suite 1417, Chicago, IL 60611. E-mail:

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Received February 18, 2014

Accepted June 09, 2014

Copyright © by the Congress of Neurological Surgeons