Predictors of Long-Acting Injectable Antipsychotic Medication Use in Patients with Schizophrenia Spectrum, Bipolar, and Other Psychotic Disorders in a United States Community-based, Integrated Health System

Long-acting injectable (LAI) antipsychotics improve patient outcomes and are recommended by treatment guidelines for patients with limited medication adherence in schizophrenia spectrum, bipolar, and other psychotic disorders. Reports of LAI antipsychotic use in these disorders and if use aligns with treatment guidelines are lacking. This study aimed to report patient characteristics associated with LAI antipsychotic use in these disorders. Retrospective observational study of patients ≥18-years-old with bipolar or psychotic disorders at a large, integrated, community-based health system. Patient demographic and clinical characteristics served as exposures for the main outcome of adjusted odds ratio (aOR) for LAI versus oral antipsychotic medication use from 1/1/2017 to 12/31/2023. There were N=2,685 LAI and N=31,531 oral antipsychotic users. Being non-white (aOR=1.3-2.0; p<.0001), non-female (aOR=1.5; p<.0001), from a high deprivation neighborhood (NDI, aOR=1.3; p<.0007),having a higher body mass index(BMI, aOR=1.3-1.7; p<.0009), having a schizophrenia/schizoaffective (aOR=5.8-6.8; p<.0001), psychotic (aOR=1.6, p<.0001), or substance use disorder (aOR=1.4; p<.0001), and outpatient psychiatry (aOR=2.3-7.5; p<.0001) or inpatient hospitalization (aOR=2.4; p<.0001) utilization in the prior year with higher odds and age ≥40 (aOR=0.4-0.7; p<.0001) or bipolar disorder (aOR=0.9; p<.05) were associated with lower odds of LAI use. Non-white, non-female, age 18-39, and high NDI patients had higher LAI use regardless of treatment adherence markers. Smoking and cardiometabolic markers were also associated with LAI use. Demographic and clinical factors are associated with increased LAI use irrespective of treatment adherence. Research on utilization variation informing equitable formulation use aligned with treatment guideline recommendations is warranted.