OBJECTIVES: The primary objective was to determine differences in long-acting injectable (LAI) antipsychotic use among racial and ethnic populations. Secondary objectives were to assess if discontinuation rates differed between agents and race/ethnicity.

METHODS: International Classification of Diseases, 10th edition (ICD-10) codes were used to identify adult patients with schizophrenia and related disorders (18-64 years) who received a LAI antipsychotic between 2016-2020 using MarketScan Multi-State Medicaid databases^®. Pharmacy claims for first- and second-generation LAI antipsychotics were identified using National Drug Code (NDC) numbers. Cochran-Mantel-Haenszel tests and odds ratio estimators were used to investigate conditional association between race/ethnicity (i.e., White, Black, Hispanic, other) and medication (i.e., individual, generation), while controlling for age, gender, health plan, and year LAI antipsychotic was first prescribed. Kaplan-Meier survival curves were examined, and stratified log-rank tests were conducted to compare the time until discontinuation distributions across race/ethnicity.

RESULTS: A total of 37,712 patients (mean age: 39± 12.7; 62% male) with LAI antipsychotic use was included in the final analysis. Approximately 22% of patients received first-generation LAI antipsychotics and 78% of patients received second-generation LAI antipsychotics. Blacks received a first-generation LAI antipsychotic more often than Whites (OR: 1.64 95% [1.56, 1.73], Hispanics (OR: 1.46 95% [1.21, 1.75]) and others (OR: 1.44, 95% [1.21, 1.75]). Whites discontinued fluphenazine decanoate, a first-generation LAI antipsychotic, earlier in comparison to Blacks (p=0.02). No other significant differences in discontinuation rates across race/ethnicity were found.

CONCLUSIONS: Despite the absence of significant differences in the second-generation LAI antipsychotic discontinuation rates between Blacks and other race/ethnic groups, Blacks received second-generation LAI antipsychotics significantly less often than any other group. Blacks may be at an increased risk for long term complications (e.g., tardive dyskinesias) with greater first-generation LAI antipsychotic use. Further studies are needed to determine why these differences (e.g., prescriber bias, patient preference) may be occurring.