Correlation between cardio-pulmonary exercise test variables and health-related quality of life among children with congenital heart diseases

BackgroundHealth-related quality of life (HR-QoL) stands as a determinant “patient-related outcome” and correlates with cardio-pulmonary exercise test (CPET) in adults with chronic heart failure or with a congenital heart disease (CHD). No such correlation has been established in pediatric cardiology.Methods and results202 CHD children aged 8 to 18 performed a CPET (treadmill n = 96, cycle-ergometer n = 106). CHD severity was stratified into 4 groups. All children and parents filled out the Kidscreen HR-QoL questionnaire. Peak VO2, anaerobic threshold (AT), and oxygen pulse followed a downward significant trend with increasing CHD severity and conversely for VE/VCO2 slope. Self-reported and parent-reported physical well-being HR-QoL scores correlated with peak VO2 (respectively r = 0.27, p < 0.0001 and r = 0.43, p < 0.0001), percentage of predicted peak VO2 (r = 0.28, p = 0.0001 and r = 0.41, p < 0.0001), and percentage of predicted VO2 at AT (r = 0.22, p < 0.01 and r = 0.31, p < 0.0001). Significant correlations were also observed between several HR-QoL dimensions and dead space to tidal volume ratio (VD/VT), oxygen uptake efficiency slope (OUES), oxygen pulse but never with VE/VCO2 slope. The strongest correlations were observed in the treadmill group, especially between peak VO2 and physical well-being for parents (r = 0.57, p < 0.0001) and self (r = 0.40, p < 0.0001) reported HR-QoL.ConclusionsPeak VO2 and AT are the two CPET variables that best correlated with HR-QoL in this large pediatric cohort, parents' reports being more accurate. If HR-QoL is involved as a “PRO” in a pediatric cardiology clinical trial, we suggest using parents related physical well-being HR-QoL scores.Clinical trial registration: ClinicalTrials.gov (number NCT01202916).