Initiation of pharmacotherapy for alcohol use disorder in Japan: a longitudinal descriptive study

Alcohol use disorder (AUD) is common worldwide, but the proportion of patients receiving pharmacotherapy remains low. In Japan, patterns of pharmacotherapy initiation for AUD have not been fully characterized. Here, we quantified the cumulative incidence of pharmacotherapy initiation among patients newly diagnosed with AUD in Japan.

We conducted a descriptive study using a Japanese insurance claims database. We created annual cohorts of adults aged 20-64 years who were newly diagnosed with AUD during fiscal years (FYs) 2012-21. Cumulative incidence for pharmacotherapy initiation was estimated, with death treated as a competing risk.

The study included 13 936 patients. Across FY 2012-21 cohorts, mean age was 43.3-44.8 years and men accounted for 72.6%-79.3% of each cohort. At cohort entry (Day 0), the cumulative incidence of pharmacotherapy initiation rose from 18.0% in FY 2012 to 35.2% in FY 2021. The 1-year corresponding cumulative incidences were 28.1% and 44.9%, respectively. Market approval of acamprosate (FY 2013) and nalmefene (FY 2018) and the publication of Japan's AUD treatment guideline (FY 2018) were each followed by marked year-on-year increases in pharmacotherapy initiation.

Although the observed incidence may have been inflated by Japan's reimbursement policy, which requires an AUD diagnosis before medication can be prescribed, pharmacotherapy initiation exceeded that reported in other countries and has increased steadily since FY 2012. Introduction of new drugs and guideline dissemination appear to have accelerated treatment initiation and substantially altered treatment practice. These findings can help clinicians and policy-makers close the persistent treatment gap.