BMJ  2006;333:501 (2 September), doi:10.1136/bmj.333.7566.501-a

Letter

Spironolactone and risk of upper gastrointestinal events

Causality remains unconvincing

The first 150 words of the full text of this article appear below.

EDITOR—I can draw only one certain conclusion from the study reported by Verhamme et al1: it is unwise to ascribe causality to an association demonstrated by a case-control study. The authors have shown that people who get gastrointestinal bleeds are four to six times more likely to be taking spironolactone than those who don't get such bleeds. Does this mean that spironolactone causes gastrointestinal bleeding? If it does, then antacids (odds ratio 3.52) must also cause gastrointestinal bleeding. And proton pump inhibitors and H2 antagonists (odds ratio 2.83) must be more likely to cause gastrointestinal bleeding than aspirin or anticoagulants (odds ratio 2.16 for both).

There are two possible explanations for the authors' findings: spironolactone causes gastrointestinal bleeding, and people who are given spironolactone are inherently more likely to get gastrointestinal bleeding.

The authors have tried to compensate for the known risk factors for gastrointestinal bleeding, but . . . [Full text of this article]

Gruffydd P Jones, general practitioner

Meddygfa Waunfawr, Caernarfon, Gwynedd LL55 4YY gruffydd_jones@yahoo.se


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Relevant Article

Spironolactone and risk of upper gastrointestinal events: population based case-control study
Katia Verhamme, Georgio Mosis, Jeanne Dieleman, Bruno Stricker, and Miriam Sturkenboom
BMJ 2006 333: 330. [Abstract] [Full Text] [PDF]

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