(270) A dose of weekly supervised exercise helps to protect lung function in children and young people with cystic fibrosis

Background: INSPIRE-CF was a randomized controlled trial that evaluated the effects of a once-weekly, individually supervised exercise training session on lung function in children and young people with cystic fibrosis.

Methods: Participants were randomized by minimization into 2 groups: control and exercise. Both groups received specialist CF care, but the exercise group also received a once-weekly, individually supervised exercise training session at a local fitness facility. Exercise training included 45-60 minutes of high intensity interval training and strength training. Spirometry and a multiple-inert gas washout test were completed at baseline and 24-month assessment points. The primary outcome measure was change in FEV₁ z-score at 24-month assessment.

Results: A total of 71 participants (control=34; exercise=37) aged 10±3 years (range 6-15) were enrolled into INSPIRE-CF. Participants in the exercise group attended a mean of 63±15% of all training sessions, ranging between 17-99 weeks out of a total of 104 weeks. At baseline and 24-month assessment points there were no significant between group differences in FEV₁, FVC, FEF_25-75 and LCI. Multilevel mixed model analysis showed that both groups had experienced a significant deterioration of -0.002 in FEV₁ z-score (95%CI -0.005, -0.00001; p=0.05) for every week that they were enrolled in the study, which equated to a deterioration of 1.5% in FEV₁ annually (0.1 z-score; 95%CI -0.26, -0.001; p=0.05). However, there was also a significant positive interaction between FEV₁ z-score and the total number of weeks of exercise training completed (0.02; 95%CI 0.01, 0.04; p=0.01). Children who exercised more regularly offset some of the deterioration in FEV₁ z-score that they might otherwise have experienced. Extrapolated data showed that children who attended at least 52 weeks of training over 24-months might expect an improvement of 1.0 in FEV₁ z-score (95%CI 0.5, 2.1; p=0.01), which equated to an improvement of 7.5% in FEV₁ annually (Figure 1). This effect was not realized in children who did not attend regular exercise sessions. There was also a significant dose related effect of exercise on both FVC and FEF_25-75. A dose related effect was not demonstrated in LCI.

Conclusions: Anticipated longitudinal improvements in lung function from a weekly supervised exercise intervention were not observed. However, participants who attended regular fortnightly exercise sessions that included high intensity interval training and strength exercises could expect an increase of as much as 7.5% in FEV₁ annually. The clinical implication of this finding is that physiotherapists should continue to actively encourage all children and young people with CF to exercise, irrespective of lung disease severity, but should be aware that sporadic and inconsistent participation in exercise is unlikely to preserve or slow the deterioration of lung function.

Acknowledgements: INSPIRE-CF was funded by Great Ormond Street Hospital Children’s Charity (#V1252), and was registered as a clinical trial at the U.S. National Institutes of Health (#NCT01889927). Acknowledgements to: Prof. Angie Wade, Dr. Paul Aurora, Dr. Alessandro Giardini, Paul Rayner and Laura Sarria-Jaramillo.

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