Transitioning from Once-Monthly to Once-Every-3-Months Paliperidone Palmitate Among Veterans with Schizophrenia

Compared to once-monthly paliperidone palmitate (PP1M), once-every-3-months paliperidone palmitate (PP3M) reportedly increases treatment adherence. The objective of this study was to compare treatment patterns, utilization, and costs among Veterans Health Administration (VHA) patients with schizophrenia who transitioned to PP3M versus those remaining on PP1M.

Adult VHA patients with ≥2 health care encounters (inpatient or outpatient) that included a schizophrenia diagnosis who initiated PP1M between January 1, 2015, and March 31, 2018 (identification period) were included in this exploratory retrospective cohort study. Propensity scores were used to match cases (PP1M users who transitioned to PP3M during the identification period) with controls (any patient initiating PP1M during the identification period). Data were assessed until death, health plan disenrollment, or study end. Outcomes were compared using chi-square and t-tests.

A total of 257 eligible PP3M and 2973 eligible PP1M patients were identified among adult VHA patients; mean ages were 53.1 and 53.7 years, respectively. After propensity score matching, the PP3M and PP1M cohorts each held 111 patients. Comorbidities of patients treated with PP3M versus PP1M, respectively, included anxiety (12.5% vs 20%; standardized difference [STD] = 20.6), tobacco use (28.4% vs 43.2%; STD = 31.2), depressive disorder (26.5% vs 36.2%; STD = 21.1), and substance abuse (37.4% vs 44.2%; STD = 13.9). For the PP3M cohort, adherence (proportion of days covered ≥80%) to any antipsychotic agent was higher (78.4% vs 57.7%, P = 0.0009), and all-cause inpatient lengths of stay (LOS) were shorter (3.0 vs 8.3 days, P = 0.0354). Increased all-cause pharmacy costs with PP3M were offset by reduced all-cause medical costs, resulting in overall health care cost-neutrality.

Relative to those remaining on PP1M, VHA patients with schizophrenia who transitioned to PP3M experienced improved antipsychotic medication adherence and significantly shorter all-cause inpatient LOS; costs remained neutral.