Ten-year Incidence of Chagas Cardiomyopathy among Asymptomatic, T. cruzi Seropositive Former Blood Donors
Background—Very few studies have measured disease penetrance and prognostic factors of Chagas cardiomyopathy among asymptomatic T. cruzi infected persons.
Methods and Results—We performed a retrospective cohort study among initially healthy blood donors with an index T. cruzi seropositive donation and age, gender and period matched seronegatives in 1996-2002 in the cities of Sao Paulo and Montes Claros, Brazil. In 2008-2010, all subjects underwent medical history, physical examination, electro- and echocardiograms (EKG and Echo). EKG and Echo results were classified by blinded core laboratories and records with abnormal results were reviewed by a blinded panel of three cardiologists who adjudicated the outcome of Chagas cardiomyopathy. Associations with Chagas cardiomyopathy were tested with multivariate logistic regression. Mean follow-up time between index donation and outcome assessment was 10.5 years for the seropositives and 11.1 years for the seronegatives. Among 499 T. cruzi seropositives, 120 (24%) had definite Chagas cardiomyopathy and among 488 T. cruzi seronegatives 24 (5%) had cardiomyopathy, for an incidence difference of 1.85 per 100 person-years attributable to T. cruzi infection. Of the 120 seropositives classified as having Chagas cardiomyopathy, only 31 (26%) presented with ejection fraction below 50, and only 11 (9%) were classified as NY Heart Association class II or higher. Chagas cardiomyopathy was associated (p<0.01) with male sex, a past history of abnormal EKG and the presence of an S3 heart sound.
Conclusions—There is a substantial annual incidence of Chagas cardiomyopathy among initially asymptomatic T. cruzi seropositive blood donors, although disease was mild at diagnosis.
- Received July 2, 2012.
- Accepted December 21, 2012.
- Copyright © 2013, Circulation