Background--Previous studies have shown that for the treatment of subarachnoid hemorrhage (SAH), outcomes are improved but costs are higher at hospitals with a high volume of admissions for SAH. Whether regionalization of care for SAH is cost-effective is unknown.

Methods and Results--In a cost-utility analysis, health outcomes for patients with SAH were modeled for 2 scenarios: 1 representing the current practice in California in which most patients with SAH are treated at the closest hospital and 1 representing the regionalization of care in which patients at hospitals with <20 SAH admissions annually (low volume) would be transferred to hospitals with 20 SAH admissions annually (high volume). Using a Markov model, we compared net quality-adjusted life-years (QALYs) and cost per QALY. Inputs were chosen from the literature and derived from a cohort study in California. Transferring a patient with SAH from a low- to a high-volume hospital would result in a gain of 1.60 QALYs at a cost of $10 548/QALY. For transfer to result in only borderline cost-effectiveness ($50 000/QALY), differences in case fatality rates between low- and high-volume hospitals would have to be one fifth as large (2.2%) or risk of death during transfer would have to be 5 times greater (9.8%) than estimated in the base case.

Conclusions--Transfer of patients with SAH from low- to high-volume hospitals appears to be cost-effective, and regionalization of care may be justified. However, current estimates of the impact of hospital volume on outcome require confirmation in more detailed cohort studies.