Thursday, April 30, 2015

Breaking News: Snus Benefits Heart Attack Survival

I reported in this blog 10 months ago that data from a Swedish study in Circulation, the journal of the American Heart Association, actually suggested that snus users had a lower death rate after a heart attack than non-users of tobacco (here).  Instead, the journal and the study’s authors promoted their work by claiming that snus poses a grave risk. 

In reviewing the study, Carl Phillips and I found it seriously flawed.  We particularly noted a glaring omission: The authors did not provide death rates among non-users of tobacco as a referent group for tobacco users.  We used information from the study to produce the following estimate for non-users.

Death Rates Among 21,220 Swedes After a Heart Attack, According to Tobacco Use
Tobacco UseDeaths per 100,000 persons per year
Continuing Snus Users18.7
Snus Users Who Quit9.7
Continuing Smokers28.4
Smokers Who Quit13.5

*Rodu-Phillips estimate; others are from the original study.

In sum, all snus users fare better after a heart attack than people who don’t use tobacco at all.  On June 30, 2014, we wrote the editor of Circulation, asking the study authors to correct errors in their original report, and address our conclusion on snus use. 

Our letter has just been published (reference here), along with the authors’ response.  Although they corrected a significant error that had been overlooked “by all coauthors and 4 reviewers,” they did not respond to our request for confirmation or revision of our estimate.  That effectively confirms our interpretation: Among Swedes who suffer a heart attack, continuing snus users have better survival than non-users.  Snus users who quit after a heart attack have the best survival of all.

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