Monday, August 13, 2012

Unquestionable costs

Back in 2009, BERL told us that harmful alcohol use cost New Zealand's health system $286 million dollars for the 2005/06 year. There were a few problems with their method. It's worth revisiting these now that a new BERL number on alcohol health costs is out. I'd critique their current numbers except, well, I'll come back to that one.

The BERL report was modelled on an Australian study by Collins and Lapsley. Collins and Lapsley used a table of alcohol aetiological fractions to assign health costs. So if alcohol is responsible for 100% of alcoholic liver cirrhosis, 100% of the costs of alcoholic liver cirrhosis are attributed to alcohol. For some disorders, alcohol consumption reduces costs to the health system. In particular, cardiovascular disease is reduced by alcohol consumption. So while someone consuming 8 standard drinks per day is likely to blow his liver out (and impose costs on the "treating bad livers" part of the health system), he'll likely have pretty clean arteries (and reduce costs on the "fixing plugged arteries" part of the health system). To get a measure of net costs you take all the fractions, some positive and some negative, and multiply by the costs of each to the health system. This will remain an imperfect measure of aggregate health costs: if moderate drinkers live longer, they'll impose greater total costs on the health system by living longer than teetotalers; if heavy drinkers die early, they'll cost the health system money early on but save the system money in the longer term. But the method gives you a first cut.

So, what did BERL do? They took Collins and Lapsley's table and surgically removed any disorders for which alcohol provided protective effects. Why? Footnote 15:
A related, but separate, issue is that of the beneficial consequences of drug consumption.  This report concentrates specifically on the social costs of harmful use.  It does not analyse the impacts from non-harmful use, such as any protective health effects of alcohol consumption.  That is, beneficial impacts of alcohol use are not included as cost offsets.
They do a bunch of handwaving about how health benefits are contentious. But their source document, Collins and Lapsley, included those benefits. And it's not a great out to say that there are no medical benefits once you get past 4 standard drinks per day. Sure, that's about where aggregate mortality risk goes past the baseline for teetotallers. But that curve is drawn for net effects: assuming away the benefits side puts a pretty big thumb on the scale in measuring total costs to the health system, especially when metastudies like Corrao's find strong cardioprotective effects well into the range where total mortality effects are pretty negative.

So after assuming away any possible health benefits from alcohol use, BERL found that alcohol imposed a large burden on the New Zealand health system. We didn't have the resources to reverse-engineer their pretty shonky zeroing-out of potential health benefits when we critiqued their study but simply noted it as something that made their figures rather higher than they should have been.

Anyway, BERL has a new figure out on costs of alcohol to Canterbury's health system. Or so reports the Christchurch Press. Their reporter, Georgina Stylianou, seems to be running off the press release here. She interviews a bunch of the usual suspects about just how awful alcohol is. Any fact checking on the figure? No. Why? The paper isn't yet released.
The report will be released in full this week and will show the range of conditions in which alcohol is a contributing factor.
Since I can't critique their new figures, I'll remind folks about what was wrong with their figures last go-round. I wonder if they've fixed anything.

It's not encouraging that the Christchurch Press seems to be playing into the media strategy that BERL and CDHB here are running: get a story on the press release, maybe another one when the report is made available; get the figures into public debate but don't let anybody have a chance at critiquing them. I'd hoped for better.

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