OBJECTIVES : To describe and compare adherence to antipsychotics (APs), healthcare resource utilization (HRU), and costs pre- and post-paliperidone palmitate every-three month (PP3M) initiation in patients with schizophrenia.

METHODS : Medicaid data from IA, KS, and MO from 1/2014 to 3/2017 was used to identify adults with ≥1 PP3M claim (first claim is the index date), ≥12 months of pre-index enrollment, and ≥2 schizophrenia diagnoses. Generalized estimating equation models were used to assess linear trends in adherence to APs, HRU, and costs over the 4 quarters pre-index, and also, to compare monthly HRU and costs 6 months pre- and 12 months post-index as well as adherence to APs 12 months pre- and post-index.

RESULTS : Among the 578 patients who initiated PP3M, the mean age was 43.0 years and 64.9% were males. In baseline quarters closer to PP3M initiation, adherence to APs increased from 58.7% to 68% (p= 0.0003), the proportion of patients with ≥ 1 inpatient visit decreased from 15.1% to 12.3% (p= 0.0291), monthly number of ER visits decreased from 0.09 to 0.07 (p= 0.0400), and monthly medical costs decreased from $1,825 to $1,387 (p=0.0080), mostly driven by a decrease in inpatient costs (from $412 to $187; p= 0.0040), while pharmacy costs increased (from $908 to $1,119; p<0.0001), resulting in similar total costs (from $2,733 to $2,506; p= 0.3200). For patients with ≥12 months of follow-up (n=269), adherence to APs increased (odds ratio=1.50; p=0.0016). Compared to the 6 months pre-index, the 12 months post-index pharmacy costs slightly increased ($1,317 vs $1,203; p=0.0040), but medical ($1,591 vs $1,587; p=0.9280) and total costs ($2,908 vs $2,791; p=0.3880) remained similar.

CONCLUSIONS : Adherence to APs and pharmacy costs increased while HRU and medical costs decreased in quarters closer to PP3M initiation. Adherence to APs increased and total costs remained similar from pre- to post-PP3M initiation.