Cost-Sharing Increase, Medication Adherence, and Hospitalizations in Schizophrenia Patients: A Natural Experiment

Increases in medication cost-sharing rates remain a controversial system-wide cost-containment measure for chronic mental health patients. The objective was to investigate the effects of cost-sharing increases on adherence to prescribed antipsychotic medication and psychiatric hospitalizations among patients with schizophrenia. In July 2012, a Spanish National Law raised the cost-sharing rate from 0 to 10% for pensioner outpatient medication while cost-sharing remained at 0% for other socioeconomic groups. To estimate the effects of the reform, we analyzed the prevalent adult schizophrenic population of Valencia, Spain, followed up 1 year before and after the Law took effect. We used a quasi-experimental design with a patient fixed-effects difference-in-differences regression to evaluate the reform effects on antipsychotic medication adherence, prescription, and hospitalization rates. A total of 5,672 included patients were exposed to the reform, whereas 5,545 were not. There were no differences in adherence, prescription, or hospitalization rates between exposed and nonexposed patients prior to its implementation. The odds ratio of exposed patients remaining adherent to issued prescriptions after the reform took effect were 0.70 99% confidence interval (CI 0.66-0.75), in relation to the nonexposed group. Additionally, the reform was associated with a reduction in exposure to antipsychotic medication (odds ratio (OR) 0.85, 99%CI 0.83-0.88) and an increase in hospitalization risk (OR 1.13, 99% CI 1.05-1.23) during the first year after implementation. Policies raising the cost-sharing rate of medication for patients with schizophrenia are simultaneously associated with unintended effects. We report decreases in antipsychotic exposure and increases in hospitalization rates that lasted for 1 year after follow-up.