OBJECTIVES: The main objective of this study was to assess the prescribing patterns of long-acting injectable (LAI) antipsychotics in an older adult population. Secondary objectives were to determine if there were differences in treatment discontinuation rates between different LAI agents and race/ethnicity.

METHODS: Merative^® MarketScan^® Multi-State Medicaid Databases (2017-2021) were used to identify patients 65 years or older who were prescribed a LAI antipsychotic. Pharmacy claims for LAI antipsychotics were referenced via NDC numbers by brand/generic name and dose. International Classification of Diseases, 10^th edition (ICD-10) codes were used to identify older adults diagnosed with schizophrenia, schizotypal or schizoaffective disorders. Those with dementia or related disorders were excluded. Cochran-Mantel-Haenszel tests and odds ratio estimators explored the conditional association between race/ethnicity (i.e., Black, White, Hispanic, other) and medication (i.e., individual, generation), while controlling for age, gender, and health plan. Kaplan-Meier survival curves were evaluated, and stratified log-rank tests were completed to compare the time until discontinuation distributions across race/ethnicity.

RESULTS: A total of 528 older adults (59% female) with an average age of 70.4± 5.5 years met inclusion criteria for final analysis. The most commonly used LAI antipsychotics included paliperidone palmitate-1 month (~35%), haloperidol decanoate (~24%), and risperidone microspheres (~15%). Approximately 31% received LAI first generation antipsychotics (FGA) and 69% received LAI second generation antipsychotic (SGA); however, Blacks (n=204) received LAI FGA more often than Whites (n=283); (OR: 1.67 95% [1.13, 2.45]). When controlling for age, gender, and race/ethnicity, LAI FGA showed earlier discontinuation rates compared to LAI SGA (p= 0.03).

CONCLUSIONS: Despite a limited sample, LAI FGA showed treatment discontinuation significantly earlier compared to LAI SGA. Furthermore, Blacks were prescribed LAI FGA at a higher rate than Whites, which may contribute to poor health outcomes in this older underserved population. Futures studies are needed to establish a causal relationship.