Medication discontinuation with depot and oral antipsychotics in outpatients with schizophrenia: comparison of matched cohorts from a 12-month observational study

Aims: This study compared all-cause medication discontinuation (any switch, augmentation or medication discontinuation) in matched cohorts of patients with schizophrenia who were initiated on depot or oral antipsychotics. Other objectives included between-group comparisons of resource use, and clinical and functional outcomes. Methods: This post hoc analysis of a one-year, multicentre, prospective, observational study included outpatients with schizophrenia who required a change in their antipsychotic medication because of a physician-perceived risk of medication non-adherence. Patients were matched 1 : 1 using an optimal algorithm with rank-based Mahalanobis distances. All-cause medication discontinuation was compared using the Klein and Moeschberger test for survival and hazard ratios (HR) with 95% confidence intervals (CI) were calculated using a Cox proportional hazards model, stratifying on matched pairs. Results: Forty patients who initiated a depot antipsychotic could be matched to patients who initiated an oral antipsychotic. Fewer depot-treated patients discontinued their antipsychotic medication at least once compared with oral-treated patients [20% (8/40) vs. 40% (16/40)]. Depot-treated patients discontinued their medication later (Klein and Moeschberger test p = 0.025) and were less likely to discontinue their initial antipsychotic medication [HR = 0.33 (95% CI, 0.12-0.92), p = 0.033] than oral-treated patients. There were few differences in resource use and no differences in clinical and functional outcomes between cohorts. Conclusion: In this matched-cohort analysis, patients with schizophrenia who were considered to be non-adherent with their prior oral antipsychotics were less likely to discontinue their medication for any cause if they were initiated on depot compared with oral antipsychotics.