Thursday 26 November 2020

An awkward study about minimum pricing

There's a study about minimum pricing in pre-print at the Lancet looking at the impact of minimum pricing on alcohol-related A & E attendances. A glance at its (many) authors suggests that they were hoping to find a drop in attendances after minimum pricing was introduced.

Alas for them, they didn't.

The study looks at 8,746 people who attended A & E in Glasgow, Edinburgh, Liverpool and Sheffield, the latter two being the control groups. All the subjects were interviewed by nurses and the study looks at the 'changes in the proportion of attendees with alcohol-related attendance in Scotland and England before and after the introduction of the MUP'.   

They found that the trend was stable in Scotland but fell in England. Awkward. They also found that binge-drinking among A & E attendees rose in Scotland but decreased in England. Oops. Furthermore...

Based on marginal analysis, it is estimated that an additional 1.0% (95% CI -0.7% to 2.7%) of the ED [emergency department] attendances were alcohol-related than would have been the case in the absence of MUP.

We estimated that approximately 258 attendances at ED were alcohol-related as a result of the introduction of MUP (95% CI -191 to 707).

Here's how this looks in graphs:

The real fun comes when the authors try to dismiss and downplay their own findings.
In summary, we did not find evidence for the introduction of MUP in Scotland impacting on alcohol-related harms within the ED setting. 
You did though, didn't you? Just nor in the direction you expected.

However, the broader evidence base is more consistent with an effect of MUP on both alcohol consumption and harms.

Ah, the broader evidence base! The one that consists of theoretical models and wishful thinking. 

This study is part of a wider evaluation programme coordinated by Public Health Scotland to inform the decision by the Scottish Parliament as to whether they will vote for MUP to continue following the sixth year of implementation. Therefore, we should interpret the results with caution and should not draw conclusions regarding the wider societal impact of MUP on alcohol harm purely based on this study.

Can you imagine them saying this if the study had found that minimum pricing was associated with a decline in alcohol-related A & E attendances? Such uncharacteristic humility! But at least they're honest about why they're being so modest - it's pure politics.

It will be interesting to see how this study looks once the reviewers have stuck their oar in - or if the Lancet decides not to publish such an inconvenient piece of research after all.

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