Healthcare resource utilization of second-generation long-acting injectable antipsychotics in schizophrenia: risperidone versus paliperidone palmitate.

OBJECTIVE: This retrospective longitudinal cohort study aimed to compare treatment patterns, healthcare resource utilization (HRU), and costs in patients with schizophrenia treated with second-generation antipsychotic long-acting injectables (SGA-LAIs): biweekly risperidone LAI versus once-monthly paliperidone palmitate.

METHODS: Patients who initiated risperidone LAI or paliperidone palmitate between 1 July 2007 and 31 December 2012 (index date) were identified from the Truven MarketScan Commercial, Medicare Supplemental, and Medicaid Multi-State insurance databases. Outcomes were assessed 12 months after the index date. Propensity score matching (1:1) based on patients' demographics and comorbidities was conducted. Outcome differences between the two cohorts were evaluated using t-tests for continuous variables, chi-square tests for categorical variables, and Wilcoxon rank-sum tests for count and cost variables. Regression models estimated the difference in medication use and adherence, likelihood of HRU, number of HRU events, and healthcare costs when comparing risperidone LAI versus paliperidone palmitate, while further adjusting for patient characteristics and pre-index HRU.

RESULTS: Patient characteristics were well balanced between the two cohorts (n = 499 each). Significantly lower discontinuation rates (36.5% vs. 53.3%; p < 0.001) and longer days of LAI coverage (233.6 vs. 131.7 days; p < 0.001) were observed in the paliperidone palmitate cohort versus the risperidone LAI cohort, respectively. Patients treated with paliperidone palmitate were 12.5 (95% confidence interval [CI]: 9.0-17.8) and 11.7 (95% CI: 8.0-17.4) times more likely to be adherent based on medication possession ratio and proportion of days covered, respectively (p < 0.001). Patients treated with paliperidone palmitate had reduced likelihood of hospitalization (adjusted odds ratio [95% CI]: 0.72 [0.55-0.95]), fewer emergency department (ED) visits (adjusted incidence rate ratio [aIRR]: 0.67 [0.61-0.73]) and reduced length of inpatient stay (aIRR: 0.86 [0.82-0.90]), which resulted in lower monthly inpatient hospitalization costs (-$77.58; p = 0.038) and ED visits (-$9.77; p = 0.021) relative to risperidone LAI.

LIMITATIONS: Pharmacy costs were derived from health plan payment in the claims data and do not account for any discounts or rebates. This may have overestimated the branded drug costs in this analysis.

CONCLUSIONS: These findings highlight the value of once-monthly paliperidone palmitate in the treatment of patients with schizophrenia.