Healthcare resource savings from administering paliperidone palmitate once every 3 months instead of once every month for schizophrenia: a 12-month mirror-image analysis of real-world population-based data

Background: Inadequate adherence to antipsychotic medication remains a major driver of relapse, hospitalization, and chronic disease progression in schizophrenia. Long-acting injectable (LAI) antipsychotics may reduce healthcare costs and the risk of relapse. However, evidence regarding the switch from paliperidone palmitate once every month (PP1M) to paliperidone palmitate once every 3 months (PP3M) remains limited. Objectives: To examine the utilization of LAI antipsychotics and investigate the effect of transitioning from PP1M to PP3M on adherence and healthcare utilization. Design: This retrospective, 12-month mirror-image study used nationwide, population-based data from Taiwan to examine changes in healthcare resource utilization and costs after the transition from PP1M to PP3M. Methods: Individuals with schizophrenia who were newly prescribed PP3M after receiving PP1M for at least 12 months between 2016 and 2021 were included. Healthcare resource utilization and costs during the 12 months before PP3M initiation were compared with those during the 12 months after initiation. Risk factors for an unsuccessful transition from PP1M to PP3M were also identified. Results: Among the 4001 patients with schizophrenia spectrum disorders included in this study, 2790 (69.7%) continued PP3M treatment. A younger age, residence in suburban or rural areas, lower concomitant use of other antipsychotics, and higher use of benzodiazepine were independent risk factors for an unsuccessful transition. At 12 months after PP3M initiation, hospitalization costs decreased from NT$38,469.0 to NT$20,062.8 and emergency room visit costs from NT$692.1 to NT$360.9 (both p < 0.001). The rates of outpatient visits, emergency room visits, and hospitalizations, the length of hospital stay, and total healthcare costs also decreased significantly (all p < 0.001). Conclusion: Transitioning from PP1M to PP3M for schizophrenia treatment can significantly reduce healthcare resource utilization and costs. Notably, hospitalization and emergency room visit costs were reduced by approximately half.