The research for this article was supported by internal funds from Héma-Québec.
BLOOD DONORS AND BLOOD COLLECTION
Iron and cardiac ischemia: a natural, quasi-random experiment comparing eligible with disqualified blood donors (CME)
Version of Record online: 16 JAN 2013
© 2013 American Association of Blood Banks
Volume 53, Issue 6, pages 1271–1279, June 2013
How to Cite
Germain, M., Delage, G., Blais, C., Maunsell, E., Décary, F. and Grégoire, Y. (2013), Iron and cardiac ischemia: a natural, quasi-random experiment comparing eligible with disqualified blood donors (CME). Transfusion, 53: 1271–1279. doi: 10.1111/trf.12081
- Issue online: 10 JUN 2013
- Version of Record online: 16 JAN 2013
- Manuscript Accepted: 23 JUL 2012
- Manuscript Revised: 20 JUN 2012
- Manuscript Received: 22 FEB 2012
The theory that elevated iron stores can induce vascular injury and ischemia remains controversial. We conducted a cohort study of the effect of blood donation on the risk of coronary heart disease (CHD) by taking advantage of the quasi-random exclusion of donors who obtained a falsely reactive test for a transmissible disease (TD) marker.
Study Design and Methods
Whole blood donors who were permanently disqualified because of a false-reactive test between 1990 and 2007 in the province of Quebec were compared to donors who remained eligible, matched for baseline characteristics. The incidence of CHD after entry into the study was determined through hospitalization and death records. We compared eligible and disqualified donors using an “intention-to-treat” framework.
Overall, 12,357 donors who were permanently disqualified were followed for 124,123 person-years of observation, plus 50,889 donors who remained eligible (516,823 person-years). On average, donors who remained eligible made 0.36 donation/year during follow-up and had an incidence of hospitalizations or deaths attributable to CHD of 3.60/1000 person-years, compared to 3.52 among permanently disqualified donors (rate ratio, 1.02; 95% confidence interval, 0.92-1.13).
Donors who remained eligible did not have a lower risk of CHD, compared to donors who were permanently disqualified due to a false-reactive TD marker. Because of the quasi-random nature of false-reactive screening tests, this natural experiment has a level of validity approaching that of a randomized trial evaluating the effect of regular blood donation on CHD risk. These results do not support the iron hypothesis.