Cost-benefit analysis of second-generation antipsychotics and placebo in a randomized trial of the treatment of psychosis and aggression in Alzheimer disease

Abstract

Context: Second-generation antipsychotics (SGAs) are prescribed for psychosis, aggression, and agitation in Alzheimer disease (AD).

Objective: To conduct a cost-benefit analysis of SGAs and placebo (taken to represent a "watchful waiting" treatment strategy) for psychosis and aggression in outpatients with AD.

Design: Randomized placebo-controlled trial of alternative SGA initiation strategies.

Setting: Forty-two outpatient clinics.

Participants: Outpatients with AD and psychosis, aggression, or agitation (N = 421). Intervention Participants were randomly assigned to treatment with olanzapine, quetiapine fumarate, risperidone, or placebo with the option of double-blind rerandomization to another antipsychotic or citalopram hydrobromide or open treatment over 9 months.

Main outcome measures: Monthly interviews documented health service use and costs. The economic perspective addressed total health care and medication costs. Costs of study drugs were estimated from wholesale prices with adjustment for discounts and rebates. Quality-adjusted life-years (QALYs) were assessed with the Health Utilities Index Mark 3 and were supplemented with measures of functioning, activities of daily living, and quality of life. Primary analyses were conducted using all available data. Secondary analyses excluded observations after the first medication change (ie, phase 1 only). Cost-benefit analysis was conducted using the net health benefits approach in a sensitivity analysis in which QALYs were valued at $50,000 per year and $100,000 per year.

Results: Average total health costs, including medications, were significantly lower for placebo than for SGAs, by $50 to $100 per month. There were no differences between treatments in QALYs or other measures of function. Phase 1-only analyses were broadly similar. Net-benefit analysis showed greater net health benefits for placebo as compared with other treatments, with probabilities ranging from 50% to 90%.

Conclusions: There were no differences in measures of effectiveness between initiation of active treatments or placebo (which represented watchful waiting) but the placebo group had significantly lower health care costs.

Trial registration: clinicaltrials.gov Identifier: NCT00015548.