Real-World Treatment Patterns and Adherence to Oral Medication Among Patients with Bipolar Disorders: A Retrospective, Observational Study Using a Healthcare Claims Database

PURPOSE: This study aimed to describe real-world treatment patterns and medication adherence among patients with bipolar disorder (BD) in Japan. PATIENTS AND METHODS: Adult patients with a BD diagnosis were identified between July 2013 and February 2018, using an employment-based health insurance claims database from the JMDC Inc. Treatment patterns of target drugs (mood stabilizers, antipsychotics) and adherence (measured by the proportion of days covered [PDC]) were assessed during the first- through third-year follow-up. Adherence was also assessed for patient subgroups. RESULTS: The analyzed population included 13,788 patients with BD. They were mostly prescribed sodium valproate, lithium, or aripiprazole (range: 21.1–27.4%) across 3 years of follow-up, whereas lamotrigine was prescribed to 11.2–12.8% of patients. Benzodiazepines (70–87%) and antidepressants (52–71%) were commonly prescribed during all three follow-up periods. The mean PDC among all patients with BD was 0.51 during the first and increased to 0.61 during the third year. The mean PDC was 0.42 (first year) in patients aged <30 years and 0.49 in those aged 30–40 years. The PDC was 0.44–0.61 (depending on the drug class) in those who were prescribed a single-class target drug and 0.68–0.83 in those prescribed two drug classes concomitantly. CONCLUSION: This study documented generally low medication adherence among patients with BD, and those at young age. These patients may require more attention.