Modified Chrispin-Norman score: correlation with peak exercise capacity and efficiency of ventilation in children with cystic fibrosis.

The modified Chrispin-Norman radiography score (CNS) is used in evaluation of radiographic changes in children with cystic fibrosis (CF). We evaluated the correlation of modified CNS with peak exercise capacity (W-peak) and ventilatory efficiency (reflected by breathing reserve index-BRI) during progressive cardiopulmonary exercise testing (CPET). Thirty-six children aged 8-17 years were stratified according to their CNS into 3 groups: mild (<10), moderate (10-15), and severe (>15). CPET was performed on a cycle ergometer. Lung function tests included spirometry and whole-body plethysmography. Patients with higher CNS had lower FEV1 (p < .001), W-peak predicted (%; p = .01) and lower mean peak oxygen consumption (VO2peak/kg; p = .014). The BRI at the anaerobic threshold and at W-peak was elevated in patients with the highest CNS values (p < .001). The modified CNS correlates moderately with W-peak (R = -0.443; p = .007) and BRI (R = -0.419; p = .011). Stepwise multiple linear regression showed that RV/TLC was the best predictor of Wpeak/pred (%; B = -0.165; b = -0.494; R-2 = .244; p = .002). Children with CF who have high modified CNS exhibit decreased exercise tolerance and ventilatory inefficacy during progressive effort.