Effect of long-acting injectable antipsychotics on treatment adherence and healthcare utilization in Chinese patients with schizophrenia: a mirror-image study.

Background: Long-acting injectable (LAI) antipsychotics can improve treatment adherence in patients with schizophrenia. Despite their benefits, LAIs are underused in China compared to other countries. Little real-world evidence describes the impact of switching from oral to LAI antipsychotics on adherence and healthcare utilization in clinical practice in China, which could help address this gap.

Objectives: To understand utilization of LAI and to assess the impact of switching from oral to LAI antipsychotics on adherence and healthcare utilization.

Design: This is a retrospective, 1-year mirror-image study using electronic health records (2012-2019) from a psychiatric specialized hospital and the psychiatry department in a general hospital in China. The observation period was 1 year before and after LAI initiation in patients already receiving oral antipsychotics.

Methods: Adult patients (aged 18-65) who initiated LAIs after receiving oral antipsychotics, with schizophrenia diagnosis at least 12 months before LAI initiation were included. The date of LAI initiation was designated as the index date. Adherence to antipsychotics was assessed by the proportion of days covered. Schizophrenia-related healthcare utilization comprised the percentage of patients who had admissions, the duration of inpatient stays, the number of inpatient visits, and outpatient visits. Wilcoxon signed-rank test and McNemar's test were used for before-after comparison.

Results: Overall, 98 and 59 eligible patients were included in two hospitals, respectively. Treatment adherence (proportion of days covered) after switching increased significantly from 46% to 61% (p < 0.01) and 32% to 58% (p < 0.01), respectively. The frequency of hospital admissions (and cumulative admission days) reduced from 10.2% to 4.1% (6 days to 2 days, p = 0.11), and 55.9% to 10.2% (11 days to 2 days, p < 0.01), respectively. Outpatient visits increased from 5 to 6 visits (p = 0.10), and 7 to 9 visits (p < 0.01), respectively.

Conclusion: Consistent benefits of LAIs in enhancing treatment adherence and optimizing healthcare utilization were observed in two representative hospitals having different clinical settings and patient characteristics.