I have now written to Sarah Getty, London News Editor of the METRO and Fred Attewill, named author of yesterday’s article on painkillers and heart disease. Here is the text of my email:
I write with regard to your item in yesterday’s (July 5) edition of METRO, which was headlined “Painkillers ‘increase risk of heart disease'” and went on to claim that research showed that commonly used painkillers increased the risk of heart disease by anything from 40 to 70 percent. While the University of Aarhus study did indeed show an increased risk, it is nowhere near as large as the article’s figures suggest.
There was no link given to the research (may I suggest that articles referring to research carry links to the relevent papers?) but it would appear to be this: http://www.bmj.com/content/343/bmj.d3450 , a case control study of 32,602 patients with atrial fibrilation and 325,918 controls who did not. The researchers found that 9% of the former and 7% of the latter were users of anti-inflammatory drugs (the percentages are slightly less tan this as they have been rounded off in the abstract but this does not affect my reasoning) giving an incident rate ratio of 1.29. The incident rate ratios for new users were 1.46 (1.33 to 1.62) for non-selective NSAIDs and 1.71 (1.56 to 1.88) for COX 2 inhibitors which I suspect is the source of your writer’s claims referred to above.
Using his logic, the overall risk of heart disease is increased by 29% but this is clearly not the case; in a case-controled study it is the absolute increase which is likely to be caused by the substance under consideration. In this case, since 7% of the controls took anti-inflamatory medication without harm it is reasonable to conclude that the same percentage of the atrial fibriation group were not harmed by the drugs. The difference (2%) can be attributed to the medication. This means that 98% of cases had another cause and thus the increase in a patient’s chances of suffering atrial fibrillation is in fact 2% (to the nearest whole number).
Thus the side effect of the medication is real but nowhere near as widespread as your article suggests.
[telephone number given]
I have had an auto-response so I know it has been received. I’ll blog on any further developments.