Regional variation in longitudinal trajectories of primary care opioids prescribing across Health Boards in Scotland: a population-based study

Background: This study aims to describe the longitudinal trajectory of opioid prescribing at the practice level and assess associated factors, including Health Boards and socioeconomic status. Research design and methods: This drug utilization research used practice-level dispensing data from 2016 to 2018. Practice-level prescription opioids dispensed were quantified by the defined daily doses (DDDs) per 1000 registrants. Group-based trajectory models were used to identify groups of practices with similar trajectories based on the difference in monthly opioid utilization. Characteristics of registrants were associated with the trajectory by a conditional logistic regression and the prescription opioids dispensed by a random-effect regression model. Results: Of the 798 practices, 29.5% increased opioid prescription by an additional 100 DDDs/1000 registrants/month during 2017 and 2018. Practice in southwest Scotland tended to be categorized into the group with increasing opioid utilization. Deprived socioeconomic status was associated with increasing opioid utilization (odds ratio: 2.2; 95% confidence interval: 1.5, 3.2) or higher annual opioid utilization (coefficient: 358.2; 95% confidence interval: 327.6, 388.8). Conclusions: Increasing opioid utilization over time was related to deprived socioeconomic status associated with chronic pain conditions and inequality in pain services. Further strategies to balance inequality are needed, which needs further investigation.