- Background: Non-adherence to antipsychotic treatment is common among patients with schizophrenia and results in increased risk of relapse, rehospitalization and healthcare resource utilization (HCRU) [1-3]. This study assessed demographics, clinical characteristics and treatment patterns, including discontinuation rates, of patients with schizophrenia who were incident oral olanzapine users while exploring their adherence to oral olanzapine. Further analysis will be presented assessing HCRU and costs among those who were non-adherent versus adherent to oral olanzapine.
Methods: This retrospective claims data study utilized data from the German InGef research database from January 2018 to December 2023. Adult patients with ≥1 inpatient and/or ≥2 outpatient International Classification of Diseases, Tenth Revision (German Modification) schizophrenia diagnoses were identified. Patients with a 1-year pre-index olanzapine (oral or injectable) and clozapine treatment-free period (i.e.,Background: Non-adherence to antipsychotic treatment is common among patients with schizophrenia and results in increased risk of relapse, rehospitalization and healthcare resource utilization (HCRU) [1-3]. This study assessed demographics, clinical characteristics and treatment patterns, including discontinuation rates, of patients with schizophrenia who were incident oral olanzapine users while exploring their adherence to oral olanzapine. Further analysis will be presented assessing HCRU and costs among those who were non-adherent versus adherent to oral olanzapine.
Methods: This retrospective claims data study utilized data from the German InGef research database from January 2018 to December 2023. Adult patients with ≥1 inpatient and/or ≥2 outpatient International Classification of Diseases, Tenth Revision (German Modification) schizophrenia diagnoses were identified. Patients with a 1-year pre-index olanzapine (oral or injectable) and clozapine treatment-free period (i.e., incident oral olanzapine population) were included. Index period: oral olanzapine dispense date (January 2019–December 2022). Daily oral olanzapine intake was calculated using the milligrams prescribed as the Defined Daily Dose. Non-adherence to oral olanzapine was defined as patients who had a proportion of days covered (PDC) score of <0.8. Treatment discontinuation was defined as a gap of 60 days after the days of supply of the previous prescription of oral olanzapine without a refill. Persistence to oral olanzapine was defined as patients who did not switch or discontinue treatment in the 1-year follow-up. Descriptive comparisons are presented in the Results.
Results: Overall, 705 incident oral olanzapine patients with a schizophrenia diagnosis were included. On average, incident oral olanzapine patients had a treatment duration of 303.4 (±192) days, and 58.7% discontinued treatment with an average time until discontinuation of 157.4 (±56.8) days. Additionally, 40.9% of patients were persistent on oral olanzapine. The proportion of patients who switched to another antipsychotic before, during or after oral olanzapine discontinuation was 18.7%, with most patients switching to oral antipsychotics, namely risperidone and quetiapine (5.1% and 4.5%, respectively).
Overall, 80.4% (n=567) patients were non-adherent to oral olanzapine, and the mean PDC score among incident oral olanzapine patients was 0.5 (±0.28). Baseline demographics were similar across adherent and non-adherent groups, with 54.4% and 52.9% being male with mean ages of 47.1 and 46.2 years, respectively. Results showed a lower mean age among males versus females (40.5 vs 53.1 years). Regarding clinical characteristics, major depressive disorder and substance abuse disorders were the most prevalent across adherent and non-adherent patients (adherent: 41.3% and 31.2%; non-adherent: 46.2% and 34.9%, respectively). The average Charlson Comorbidity Index (CCI) score was also high across adherent and non-adherent patients (0.98 and 0.94, respectively).
Conclusions: This study examined the demographics, clinical characteristics, treatment patterns and discontinuation rates of incident oral olanzapine patients with schizophrenia in Germany. Although non-adherence and treatment discontinuation were observed in a substantial proportion of patients, it is important to note that this complex population had a high comorbidity burden (as indicated by high CCI scores). Notably, only a minority of patients transitioned to another antipsychotic. These results improve understanding of real-world treatment dynamics with oral olanzapine and underscore the need for tailored strategies to support adherence.…
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