Healthcare Resource Utilization 6 Months Before and After Olanzapine/Samidorphan Initiation: Real-World Assessment of Patients with Schizophrenia or Bipolar I Disorder.

Introduction: A combination of olanzapine and samidorphan (OLZ/SAM), approved by the US Food and Drug Administration (2021) for the treatment of adults with schizophrenia (SZ) or bipolar I disorder (BD-I), mitigates weight gain associated with olanzapine treatment. This study examined changes in healthcare resource utilization (HCRU) among patients with SZ or BD-I after initiating OLZ/SAM.

Methods: This retrospective analysis utilized USA-based administrative claims data from April 19, 2021 to December 31, 2022. Adults aged ≥ 18 years with SZ or BD-I who had continuous enrollment ≥ 6 months before (baseline) and after (follow-up) OLZ/SAM initiation (index) were eligible. HCRU comparisons included inpatient admissions, average number of inpatient days, emergency department (ED) visits, and outpatient visits between 6-month baseline and follow-up periods.

Results: In total, 1546 patients initiated OLZ/SAM (SZ: n = 855, mean age 39.4 years, 52.6% male; BD-I: n = 691, 38.4 years, 31.0% male). Overall, 446 (52.2%) patients with SZ and 302 (43.7%) patients with BD-I remained on OLZ/SAM during the full 6-month follow-up (median days persistent 182 and 106, respectively). In the SZ and BD-I cohorts, proportions of patients with all-cause and mental health (MH)-related inpatient admissions and ED visits significantly decreased between baseline and follow-up (all-cause: all P ≤ 0.026; MH-related: all P < 0.001). Findings were similar for disease-specific outcomes with the exception that reductions in BD-I-related ED visits were not significant. Average number of inpatient days decreased after OLZ/SAM initiation in both cohorts; in patients with BD-I, those reductions were statistically significant (all P ≤ 0.022). The proportions of patients with outpatient visits were similar between baseline and follow-up for both cohorts.

Conclusions: Results from this first real-world study assessing HCRU after OLZ/SAM initiation suggest that OLZ/SAM results in reductions in burden for patients, providers, and the healthcare system, as evidenced by reductions in acute all-cause, MH-related, and disease-specific HCRU among SZ and BD-I cohorts.