Hospitalization Rates and Therapy Costs of German Schizophrenia Patients Who are Initiated on Long-Acting Injectable Medication: A Mirror-Image Study.

Background: Long-acting injectable (LAI) antipsychotics can reduce relapse, hospitalization, and costs in patients with schizophrenia. However, real-world evidence assessing the impact of treatment with LAIs in Germany is limited.

Objective: To provide updated evidence on the impact of LAI initiation on hospitalization rates and therapy costs.

Methods: Using a mirror-image design, claims data of 850 German patients with schizophrenia who initiated treatment with LAIs during 2013-2015 was retrospectively analyzed. For the included patients, costs and resource utilization were compared for the 12 months before the index date (first initiation of LAI) and the 12 months after the index date. Annual treatment costs, hospitalization rates, ambulatory visits, sick leaves and medical aids were assessed. Two models were used to evaluate hospitalization and its costs. In model 1, hospitalization during the index date (first LAI prescription in 2013-2015) was allocated to the "pre-" time interval, while in model 2 it was neither attributed to the pre- nor to the post-index date. Regression analysis was performed to identify patients who benefited the most in terms of cost reduction from LAI initiation.

Results: Medication costs were significantly higher post-switching to LAI compared with pre-switching period (€3832 vs €799; p < 0.001). In model 1, number of hospitalizations, days hospitalized, and associated costs were significantly lower post-switching compared with pre-switching (2.3 vs 2.6; 59.2 vs 73.4; and €5355 vs €11,908, respectively; all p < 0.001). Similar results were obtained for costs in model 2 (€5355 vs €10,276; p < 0.001). Mean total costs reduced significantly from pre-switching to post-switching period in model 1 (€13,776 vs €10,418; p < 0.001). Patients with characteristics such as higher number of non-psychiatric and psychiatric inpatient stays during the pre-index period (all p < 0.05) benefited the most from cost reduction after LAI initiation.

Conclusion: In this cohort of German patients with schizophrenia, treatment initiation with LAI resulted in reduced hospitalization rates and total costs.