Comparison of Medicaid spending in schizoaffective patients treated with once monthly paliperidone palmitate or oral atypical antipsychotics.

Background: Compared to oral atypical antipsychotics (OAAs), long-acting injectable antipsychotics require less frequent administration, and thus may improve adherence and reduce risk of relapse in schizoaffective disorder (SAD) patients.
Objective: To evaluate the impact of once monthly paliperidone palmitate (PP) versus OAAs on healthcare resource utilization, Medicaid spending, and hospital readmission among SAD patients.
Methods: Using FL, IA, KS, MS, MO, and NJ Medicaid data (January 2009-December 2013), adults with ≥2 SAD diagnoses initiated on PP or OAA (index date) were identified. Baseline characteristics and outcomes were assessed during the 12month pre- and post-index periods, respectively. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to reduce confounding and compare the estimated treatment effect for PP versus OAA.
Results: A total of 10,778 OAA-treated patients and 876 PP-treated patients were selected. Compared to OAAs, PP was associated with significantly lower medical costs (PSM: mean monthly cost difference [MMCD] = -$383, p < 0.001; IPTW: MMCD = -$403, p = 0.016), which offset the higher pharmacy costs associated with PP (PSM: MMCD = $270, p < 0.001; IPTW: MMCD = $350, p < 0.001) and resulted in similar total healthcare cost (PSM: MMCD = -$113, p = 0.414; IPTW: MMCD = -$53, p = 0.697) for PP versus OAA. Reduced risk of hospitalization (PSM: incidence rate ratio [IRR] = 0.85, p = 0.128; IPTW: IRR = 0.96, p = 0.004) and fewer hospitalization days (PSM: IRR = 0.74, p = 0.008; IPTW: IRR = 0.85, p < 0.001) were observed in PP versus OAA patients. Among hospitalized patients, PP was associated with a lower risk of 30 day hospital readmission compared to OAA (IPTW: odds ratio = 0.89, p = 0.041). Limitations The Medicaid data may not be representative of the nation or other states, and includes pre-rebate pharmacy costs (potentially over-estimated). Also changes in treatment over time were possible.
Conclusions: Total healthcare costs associated with the use of once monthly PP versus OAAs appeared comparable; higher pharmacy costs for PP users were offset by lower medical costs related to fewer and shorter inpatients visits.