Correlation between cardio-pulmonary exercise test variables and health-related quality of life among

children with congenital heart diseases

Methods

Results

Amedro P. MD, MPH (a,b,d,e), Dorka R. (a), Moniotte S. MD, PhD (b), Picot M.C. MD, PhD (c), Matecki S. MD, PhD (a,d), Bertet H. (c), Guillaumont S. MD (a), Ovaert C. MD, PhD (b), Sluysmans T. MD, PhD (b), Barrea C. MD, PhD (b), Auquier P. MD, PhD (e).

(a) Pediatric and Congenital Cardiology Department, University Hospital, Montpellier, France(b) Pediatric and Congenital Cardiology, UCL, Brussels, Belgium(c) Epidemiology and Clinical Research Department, University Hospital, Montpellier, France (d) Physiology and Experimental Biology of Heart and Muscles Laboratory - PHYMEDEXP, UMR CNRS 9214 – INSERM U1046, University of Montpellier, Montpellier, France(e) Self-perceived Health Assessment Research Unit, EA3279, Public Health Department, Mediterranean Medical School, Marseille, France

Peak VO2, anaerobic threshold (AT), 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 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 QoL dimensions and VD/VT ratio, 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 QoL.

Introduction

Background: peak oxygen uptake (VO2) correlates with health related quality of life (QoL) in adults with heart failure. Cardio-pulmonary exercise test (CPET) is recommended in the follow-up of adults with congenital heart diseases (CHD). Few data is available as regards correlation between CPET and QoL among children with CHD.

202 CHD children aged 8 to 18 performed a complete CPET (treadmill n=96, cycle-ergometer n=106) in 2 tertiary care pediatric cardiology university centers (UCL St Luc, Brussels, Belgium and Montpellier University Hospital, France)CHD severity was stratified into 4 groups. All children and parents filled out the Kidscreen QoL questionnaire.This study complies with the declaration of Helsinki. It was approved by Ethics Committees in France (South Mediterranean IV) and Belgium (UCL Medical School) and was registered on ClinicalTrials.gov (number NCT01202916). Informed consent was obtained from all parents.

Conclusion

Peak VO2 and anaerobic threshold are the two CPET variables which best correlated with self and parents-reported QoL in this large pediatric cohort. If QoL is involved as a “patient related outcome” in a clinical trial in pediatric cardiology, we suggest to use parents related QoL scores.

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Table 2. Socio-demographic characteristics

CHD Total

N=202

CHD p-value France

N=106 Belgium

N=96

Sex ratio (Male/Female) 1.9 2.2 1.7 0.34

Age (Mean (SD)) 12.4 (3.0) 12.2 (2.9) 12.6 (3.2) 0.39

School class Elementary school Middle school High school Specialized education

62 (31%) 95 (48%) 26 (13%) 16 (8%)

34 (33%) 51 (49%) 13 (13%)

5 (5%)

28 (29%) 44 (46%) 13 (13%) 11 (12%)

0.38

School level Normal Advanced Repeated Dropout

131 (66%)

2 (1%) 64 (32%)

2 (1%)

68 (65%)

2 (2%) 32 (31%)

2 (2%)

63 (66%)

0 (0%) 32 (34%)

0 (0%)

0.41

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Tables

Table 1. CHD severity classification 16

Severity class 1 Mild CHD requiring no therapy or effectively treated non-operatively (catheter therapy)

Severity class 2 Moderate CHD requiring no therapy or surgically corrected (curative)

Severity class 3 Surgically treated CHD with significant residua or need for additional surgery

Severity class 4 Complex or severe CHD, uncorrectable or palliated (includes single ventricle)

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Table 4. CPET results: stratification on CHD severity

CHD Total

Severity Class

Class 1

Class 2

Class 3

Class 4

p-value (1)

Age (years)

12.4±3.0

12.4±3.3

12.0±2.8

12.4±2.9

12.9±3.2

0.40

Sex ratio (M/F) 1.9 1.5 1.5 2 3 0.17

Weight (kg) 43.4±15.0 44.5±15.6 45.1±19.0 43.2±14.3 41.2±12.8 0.62

Size (cm) 151.0±16.0 152.1±16.8 148.8±13.6 151.4±16.0 149.9±18.0 0.99

BMI (kg/m2) 18.5±3.6 18.6±3.2 19.6±5.3 18.3±3.4 17.9±2.9 0.24

Peak HR (bpm) 174.1±20.4 180.3±15.5 179.3±16.8 172.9±20.5 163.3±25.6 <0.01 *

% predicted HR 83.9±10.0 86.8±7.7 86.3±8.1 83.3±9.9 79.0±12.8 <0.01 *

Maximum load (watt) 148.5±62.3 157.8±64.8 152.5±66.2 150.0±61.4 125.7±56.9 0.13

Peak RER 1.13±0.11 1.16±0.14 1.12±0.11 1.12±0.10 1.10±0.11 0.08

Peak VO2 (ml/kg/min) 39.4±8.9 41.3±9.4 42.5±9.7 39.5±7.5 33.0±9.3 <0.001 ***

% predicted peak VO2 91.5±21.5 97.8±21.2 98.1±22.2 91.6±19.1 74.7±21.6 <0.001 ***

AT (ml/kg/min) 27.4±6.5 28.0±6.8 28.5±7.1 27.4±6.4 25.4±5.3 0.17

% predicted AT 63.5±15.0 66.4±16.3 65.8±16.2 63.4±14.2 57.3±12.6 0.01 $

VO2/HRrest (ml/beat) 3.8±1.6 3.6±1.5 4.1±1.4 3.8±1.6 4.0±1.8 0.48

VO2/HRAT (ml/beat) 8.3±2.7 8.3±2.8 8.6±2.5 8.5±2.7 7.4±2.9 0.24

VO2/HRpeak (ml/beat) 9.6±3.3 10.0±3.7 9.8±2.9 9.7±3.1 8.2±3.5 0.05 *

VE/VCO2 slope 31±6 30±6 30±4 30±6 37±8 0.02 **

OUES 732.5±276.5 765.5±349.7 772.1±195.8 739.0±260.7 637.0±261.6 0.20

VD/VTrest 19.7±8.9 20.0±7.7 18.3±12.6 19.5±8 21.9±9.5 0.47

VD/VTAT 21.1±9.4 21.6±7.9 18.4±9 20.2±9.1 26.2±11.1 0.39 *

VD/VTpeak 21.8±9.6 20.8±9.3 18.6±9.2 19.7±8.3 26.4±12.6 0.22 *

Values are presented as mean ± SD. (1) Two-sided Jonckheere trend test. Significant comparison (Chi-square, ANOVA or Kruskal-Wallis test) was denoted by $ for p<0.10, * for p<0.05, ** for p<0.01 and *** for p<0.001. BMI: body mass index.

Correlations between QoL scores and peak VO2.

Legend: Significant correlation was denoted by $ for p<0.10, * for p<0.05, ** for p<0.01 and *** for p<0.001

Correlations between QoL scores and percentage of predicted anaerobic threshold

Correlations between QoL scores and percentage predicted peak VO2

Legend: Significant correlation was denoted by $ for p<0.10, * for p<0.05, ** for p<0.01 and *** for p<0.001 Legend: Significant correlation was denoted by $ for p<0.10, * for p<0.05, ** for p<0.01 and *** for p<0.001

Correlations between self-reported QoL scores and CEPT Correlations between proxy-reported QoL scores and CEPT