Impact of Minimum Unit Pricing on Alcohol-Related Emergency Department Attendances in Scotland: A Natural Experiment Study

Background: Minimum Unit Pricing (MUP) was introduced in Scotland at 50p per unit (8g) of alcohol on 1st May 2018 to reduce alcohol consumption and associated harms. We assessed its impact on alcohol-related emergency department (ED) attendances, drinking patterns, and having an alcohol-related diagnosis amongst ED attendees. Methods: We used a natural experiment approach to compare outcomes between Scotland (intervention group) and England (comparison group). Two EDs in Scotland and two in England were recruited for one baseline and two post-intervention waves. Research nurses considered all attendees for interview, and recorded reasons for not interviewing attendees. The primary outcome was alcohol-related attendances among all recorded attendees. Secondary outcomes included alcohol-related diagnosis, binge drinking and high-risk drinking, and tested for differential effects across socioeconomic groups. Difference-in-difference regression models adjusted for age, sex and baseline covariates. Findings: 12,207 participants were recruited in Scotland and 11,248 in England. The odds ratio for an alcohol-related attendance was 1.14 (95% CI 0.90-1.44) after the introduction of MUP in Scotland relative to England, after controlling for covariates. It is estimated that an additional 1.0% (95% CI -0.7% to 2.7%) of the ED attendances were alcohol-related than would have been the case in the absence of MUP. Meanwhile, the odds for an attendee having at least one alcohol-related diagnosis increased after MUP (OR=1.25, 95%CI 1.00-1.57). There was no evidence of substantive differences in the majority of other secondary outcomes after the introduction of MUP in Scotland, or of differential effects across socioeconomic groups. Interpretation: We found no evidence that MUP impacted on alcohol-related ED attendances.