Reduced functional capacity in patients with Chagas disease: a systematic review with meta-analysis

Reduced peak oxygen uptake (VO2peak) is a common clinical finding in progressive Chagas disease. However, the disease stage in which functional impairment is detectable remains uncertain. The present study compared functional capacity between healthy controls and patients with different clinical forms of Chagas disease. A systematic review and meta-analysis (PROSPERO database CRD42017058353) was conducted following a search of the MEDLINE, Web of Science, CINAHL, and LILACS databases from September to December 2017 for articles published in English, Spanish, or Portuguese, with no date restrictions. We included studies that compared the VO2peak between healthy and Chagas disease patients, stratified according to 3 clinical forms [no apparent cardiac disease, non-dilated Chagas heart disease (CHD), and dilated CHD]. Seven cross-sectional studies were included. Chagas disease patients without apparent cardiac disease (n=208) had VO2peak values [mean difference, -1.55ml/kg/min; 95% confidence interval (CI), -4.98ml/kg/min to 1.88ml/kg/min] similar to those of healthy controls (n=105; p=0.38, I2=52%). In non-dilated CHD (n=159), VO2peak was 8.71ml/kg/min lower (95% CI, -13.99 to -3.42ml/kg/min) than in healthy controls (n=59; p=0.001, I2=75%). VO2peak was also significantly lower (mean difference, -9.30ml/kg/min; 95% CI, -11.34 to -7.25ml/kg/min) in dilated CHD patients (n=131) than in healthy controls (n=53; p<0.001, I2=0%). Exercise capacity in Chagas disease patients without apparent cardiac disease is similar to that in healthy controls. Functional impairment in Chagas disease is detectable in the early stages of cardiac involvement, even in the absence of systolic dysfunction and signs of heart failure.