Medical, Psychiatric, and Sociodemographic Predictors of Clozapine Initiation at an Academic Medical Center

Abstract

Background and Hypothesis Clozapine is an effective yet underutilized treatment for treatment‐resistant schizophrenia spectrum disorders. This study aimed to identify factors affecting clozapine prescribing patterns among patients with treatment‐resistant schizophrenia and schizoaffective disorder at an academic medical center. Study Design This retrospective combined cohort and case‐control study examined demographic, socioeconomic, medical and psychiatric characteristics to determine predictors of clozapine initiation. Eligible patients had a diagnosis of schizophrenia or schizoaffective disorder with at least two prior antipsychotic trials and were admitted to a University of Utah inpatient psychiatric facility (1/2014–3/2021). Patients who did and did not receive clozapine during the index hospitalization were compared in cohort and case‐control study arms. Study Results Twelve percent (59/477) of the cohort received clozapine during the index admission. Among the cohort (n = 477), Black patients were twice as likely to receive clozapine than White and Hispanic patients (OR 2.18, 95% CI 1.20–3.97, p = 0.008). In the case‐control analysis, patients with a greater number of previous psychiatric admissions (OR 1.14, p = 0.079) and antipsychotic trials (OR 1.40, p = 0.038) had greater odds of receiving clozapine. Homelessness was identified as a predictor against clozapine use (OR 2.77, p = 0.014). Conclusions This is the first study to identify homelessness as a predictor against clozapine use, which raises important clinical and ethical considerations. Our findings also add to the literature on clozapine prescribing discrepancies among ethnic‐minority patients. Overall, clozapine remains underutilized as the gold‐standard treatment for treatment‐resistant schizophrenia‐spectrum disorders, reinforcing a need to improve evidence‐based prescribing.