Cost-effectiveness of clozapine in patients with high and low levels of hospital use

Background: This study examined the relationship between pretreatment hospital use and the costeffectiveness 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.