Association between Subarachnoid Hemorrhage Outcomes and Number of Cases Treated at California Hospitals

Bardach NS, et al.
Stroke. 2002 Jul; 33(7):1851-6.

To determine if patients with subarachnoid hemorrhage treated at high-volume hospitals have better outcomes.

The discharge abstracts for all patients with a primary diagnosis of subarachnoid hemorrhage admitted to nonfederal hospitals in California from 1990 to 1999 were analyzed. Hospital volume, defined as the average number of subarachnoid hemorrhage cases admitted each year, was divided into quartiles. A total of 12,804 patients were admitted for subarachnoid hemorrhage through the emergency departments of 390 hospitals. Mortality rate, adverse events, lengths of stay and hospital charges were evaluated.

The mortality rate in the lowest volume quartile (49%) was larger than that in the highest volume quartile (32%). For any given annual case volume used to divide hospitals into high- and low-volume groups, the odds ratio of in-hospital mortality shows a decreased risk of death in the high-volume hospitals. With a definition of high-volume of at least 21 cases, the odds ratio of in-hospital mortality was at least 40% lower at high-volume hospitals.

Hospitals that treated more cases of subarachnoid hemorrhage had substantially lower rates of in-hospital mortality.