Treatment Discontinuation of Long-Acting Injectables or Oral Atypical Antipsychotics Among Medicaid Recipients With Schizophrenia

OBJECTIVE: Compare treatment discontinuation of atypical long-acting injectables (LAIs) and oral atypical antipsychotics (OAA) in patients with schizophrenia.

METHODS: Adult patients with schizophrenia initiating LAI including paliperidone palmitate (PPLAI), aripiprazole (ALAI), or risperidone (RLAI) and OAA were identified using the IBM MarketScan Medicaid claims database between 01/01/2010-06/30/2016. Patients had 12-months data pre and post index date (first LAI or OAA claim). Discontinuation was defined as the lack of subsequent claims for the index medication 60 (primary analysis) or 90 (sensitivity analysis) days following the exhaustion of the previous claims days’ supply. Kaplan-Meier curves and Cox proportional hazards models with inverse probability of treatment weighting (IPTW) were used to examine time to discontinuation of therapy.

RESULTS: The study population included 4,302 PPLAI (mean age: 39.4 years; female: 44.7%, Deyo-Charlson Comorbidity Index score: 0.8, number of unique mental health diagnoses: 4.2), 586 ALAI (38.0, 46.6%, 0.8, 4.7), 1,456 RLAI (41.0, 44.0%, 0.9, 4.5), and 7,029 OAA patients (40.6, 44.0%, 0.7, 3.8). All numbers are weighted. IPTW regression suggested that LAI patients had a significantly lower risk of discontinuing their therapy relative to OAA patients: hazard ratio (95% confidence interval) was 0.60 (0.56-0.64) for PPLAI, 0.69 (0.60-0.79) for ALAI, and 0.70 (0.64-0.77) for RLAI. Sensitivity analysis results and Kaplan-Meier curves were consistent.

CONCLUSIONS: PPLAI users had a significantly lower risk of discontinuing their therapy than OAA users, and also a lower risk relative to ALAI and RLAI among Medicaid recipients with schizophrenia.