OBJECTIVES: Long-acting therapy (LAT) formulations of atypical antipsychotics (AAPs) remove the need for daily medication in the treatment of schizophrenia and may improve outcomes. Little is known about LAT AAP use during inpatient admissions. This study identifies factors associated with LAT AAP use among inpatients with schizophrenia. METHODS: A retrospective analysis (2007-2010) of the Health Facts® database (Cerner Corp., Kansas City, MO) identified adult patients with a primary discharge diagnosis of schizophrenia and ≥1 order for AAP. Factors examined included demographic, clinical, and treatment setting characteristics. A bootstrapping algorithm with multilevel (hierarchical) logistic regression was used to identify factors most strongly associated with LAT AAP exposure. RESULTS: A total of 3230 admissions met inclusion criteria; 217 had LAT AAP exposure. Before regression adjustment, key factors with a significantly greater likelihood of LAT AAP use included receiving oral risperidone (85.3% vs 35.0%, P<0.001) and being treated in a facility with ≥500 beds (48.9% vs 31.5%, P=0.001). Negative associations included Caucasian race (47.9% vs 55.4%, P=0.033), receiving most other oral AAPs (varies by agent), and being treated in a facility with <500 beds (varies by categorical size). Factors not significantly associated with LAT AAP use included age, use of first-generation antipsychotics, urgent admission, and treatment in a teaching facility. The regression model had good discrimination (c-statistic = 0.85); factors associated with a greater likelihood of LAT AAP exposure were male gender (OR=1.58, P=0.005), diagnosis of chronic respiratory conditions (OR=1.64, P=0.014), affective disorders not meeting criteria for full mood disorder (OR=1.95, P=0.004), and oral risperidone (OR=11.05, P<0.001). Patients using olanzapine (OR=0.64, P=0.057) or antidepressants (OR=0.75, P=0.065) trended toward not receiving LAT AAP. CONCLUSIONS: LAT AAP use in the inpatient setting was related to gender, certain chronic conditions, specific AAP and antidepressant use, and facility size.