Risk of cardiovascular events associated with positive serology for Chagas: a systematic review

BACKGROUND: Chagas disease affects mainly poor populations in Latin America. This review assesses the evidence on the independent risk of cardiovascular events associated with positive Chagas serology. METHODS: We searched for studies using the following outcomes: death, stroke, new onset heart failure, heart failure hospitalization or evidence of left ventricular dysfunction. Studies comparing patients with positive serology for Chagas with a control group with a follow-up longer than 1 year were selected. The Medline, Lilacs and Embase databases were searched on 21 January 2011 without restrictions. RESULTS: From 5236 potentially relevant studies, 25 fulfilled the inclusion criteria. Fourteen included patients with heart failure, six with severe symptoms and nine with mild symptoms or asymptomatic patients with low ejection fraction. In four studies of patients in functional class III or IV and in three studies of patients with mild symptoms, a higher risk of death was reported among those with positive serology for Chagas. Of the 11 studies of patients without symptoms or low ejection fraction, 3 showed a higher risk of mortality related to Chagas exposure. Two of these were based on the same cohort of people aged >60 years. Overall, 8 out of the 14 heart failure studies and 2 out of the 11 heart damage studies adjusted for confounding factors. CONCLUSION: Positive serology for Chagas is associated with a higher risk of death for patients with heart failure. However, there is little evidence to link positive serology for Chagas with cardiovascular events in asymptomatic subjects.