Trends of Strong and Weak Opioid Prescriptions in Japan: A Cross-Sectional Study Based on Open Data from the National Database and Hospital Claims Data from Fiscal Years 2015 to 2021.

Trends in opioid use for patients with cancer in Japan remain unclear. This study investigated the prescription trends of strong and weak opioids in Japan and the prescription trends among patients with or without support from a palliative care team. Open data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) and administrative claims data from the University of Yamanashi Hospital from fiscal years 2015 to 2021 were used. Opioid consumption was reported using the defined daily dose (DDD) per 1000 inhabitants per day (DID) and DDD per 100 bed-days. The NDB open data showed a decrease from 0.3111 to 0.2271 in the DID for inpatients (p = 0.0001) and an increase from 0.5971 to 0.8597 in the DID for outpatients (p = 0.0003). Consumption of tramadol, a weak opioid, increased in both inpatient and outpatient settings. In University of Yamanashi Hospital, the annual percentage of opioid consumption changed little among strong opioids (98.1-97.1%) and weak opioids (1.8-2.8%) for patients supported by a palliative care team (p = 0.2842), but changed more noticeably among strong opioids (86.6-69.6%) and weak opioids (13.3-30.3%) for patients without support from a palliative care team (p < 0.001). Opioid prescription patterns in Japan changed during the 7-year study period, which indicated shifts in the types of opioids used. Additionally, the trend in opioid prescriptions was characterized by the presence or absence of palliative care team support.