Cost-effectiveness of clozapine in patients with high and low levels of hospital use. Department of Veterans Affairs Cooperative Study Group on Clozapine in Refractory Schizophrenia.

BACKGROUND

This study examined the relationship between pretreatment hospital use and the cost-effectiveness of clozapine in the treatment of refractory schizophrenia.

METHODS

Data from a 15-site randomized clinical trial were used to compare clozapine with haloperidol in hospitalized Veterans Affairs patients with refractory schizophrenia (n = 423). Outcomes were compared among those with many days in the hospital use (hereafter, high hospital users) (n = 141; mean = 215 psychiatric hospital days in the year prior to study entry) and those with few days in the hospital use (hereafter, low hospital users) (n = 282; mean = 58 hospital days). Analyses were conducted with the full intention-to-treat sample (n = 423) and with crossovers excluded (n = 291).

RESULTS

Clozapine treatment resulted in greater reduction in hospital use among high hospital users (35 days less than controls, P = .02) than among low users (21 days less than controls, P = .05). Patients taking clozapine also had lower health care costs; after including the costs of both medications and other health services, costs were $7134 less than for controls among high hospital users (P = .14) but only $759 less than for controls among low hospital users (P = .82). Clinical improvement in the domains of symptoms, quality of life, extrapyramidal symptoms, and a synthetic measure of multiple outcomes favored clozapine in both high and low hospital user groups.

CONCLUSIONS

Substantial 1-year cost savings with clozapine are observed only among patients with very high hospital use prior to initiation of treatment while clinical benefits are more similar across groups. Cost-effectiveness evaluations, and particularly studies of expensive treatments, cannot be generalized across type of use groups.