Prognostic value of cardiopulmonary exercise testing in a European cohort with cardiovascular risk factors absent of a cardiovascular disease diagnosis

Introduction: Cardiorespiratory fitness (CRF) is now considered a vital sign. Cardiopulmonary exercise testing (CPET) is the gold-standard assessment of CRF; peak oxygen consumption (VO2) and the minute ventilation/ carbon dioxide production (VE/VCO2) slope are considered primary CPET measures of CRF. More work is needed to determine the role of this exercise assessment in the primary care setting. Methods: 695 subjects (mean age: 62 +/- 13 years, body mass index: 28.9 +/- 5.3 kg/m(2), 375 female and 320 male) underwent CPET using a cycle ergometer. 95% of the cohort had one or more major cardiovascular risk factor (i. e., obesity, smoking, dyslipidemia, hypertension, diabetes); no subject was diagnosed with cardiovascular disease (CVD) at the time of CPET. Subjects were tracked for the composite endpoint of cardiovascular mortality or hospital admission. Results: Mean peak VO2, VE/VCO2 slope and peak respiratory exchange ratio were 17.8 +/- 5.8 mlO(2)center dot kg(-1) center dot min(-1), 26.7 +/- 4.1, and 1.18 +/- 0.13, respectively. There were 42 composite events during the 64 +/- 18 month tracking period. Both peak VO2 (Chi-square 16.3, p < 0.001) and the VE/VCO2 slope (Chi-square 14.9, p < 0.001) were significant univariate predictors of the composite endpoint. The VE/VCO2 slope added significant predictive value to peak VO2 and was retained in the multivariate regression (residual Chi-square 7.0, p = 0.008). Discussion: These results support the prognostic value of CPET prior to a CVD diagnosis. The prognostic value of the VE/VCO2 slope, not commonly the focus of CPET trials in patients with one or more major cardiovascular risk factors but without a confirmed CVD diagnosis, is a particularly novel finding in the current study.