Bipolar patients treated with long-acting injectable risperidone in Taiwan: A 1-year mirror-image study using a national claims database

Objective: Bipolar disorder (BD) is burdensome for patients and healthcare systems. This study evaluated changes in concomitant medication patterns, healthcare utilization, and costs after the initiation of risperidone long-acting injection (RLAI) treatment among BD patients.

Method: 287 BD patients receiving regular RLAI treatment for 1 year were identified from the Taiwan National Health Insurance Research database during 2007-2012. The bootstrapping procedure was performed to create 1000 samples to generate normally distributed data. The paired t-tests with a correction for multiple comparisons using Bonferroni correction were used to compare the proportion of patients of concomitant psychiatric medication and resource use and costs between pre- and post-RLAI periods. Rapid and non-rapid cycling stratification was performed based on the number of change-in-mood episodes within 1 year prior to the index date.

Results: The mean annual dose of RLAI was 638.41mg, which was equal to an average dose of 24.6mg every 2 weeks. The prevalence of concomitant use of conventional antipsychotics, atypical antipsychotics, lithium, and antidepressants decreased from the pre-RLAI period to the post-RLAI period by 23.75%, 31.91%, 1.29%, and 7.08%, respectively. RLAI use decreased emergency room (ER) visits, hospital admissions, length of hospital stay, and non-medication costs (all P<0.0001). The cost savings with RLAI were attributed to lower hospitalization costs in spite of higher medication costs. Moreover, rapid cycling patients (n=36) demonstrated greater reduction in ER and inpatient services with RLAI than non-rapid cycling patients (n=251).

Limitations: Of the patients who initiated RLAI, 15% of them who had regular treatment were included. Furthermore, data on measures of symptom severity, side effects, and hyperprolactinemia were not available.

Conclusion: BD patients had lower inpatient and ER utilization, and non-medication costs after using RLAI. In addition, RLAI use decreased the number of change-in-mood episodes in rapid cycling patients; which provides additional insights into the treatment of rapid cycling BD patients.