Improvement in functional exercise performance and quadriceps muscle strength after two years treatment with elexacaftor/tezacaftor/ivacaftor in people with cystic fibrosis: A prospective observational study.

BACKGROUND

As reduced exercise capacity and muscle weakness are common in people with cystic fibrosis (pwCF) and associated with worse life prognosis and quality of life, we aimed to evaluate the changes in functional exercise performance and peripheral muscle strength in pwCF after two years of elexacaftor/tezacaftor/ivacaftor (ETI).

METHODS

The 6-Minute Walk Test (6MWT), 1-Minute Sit-to-Stand Test (1STST) and measurement of Maximal isometric Voluntary Contraction of the Quadriceps (MVCQ) with a dynamometer were performed before initiating ETI and after one and two years of ETI.

RESULTS

82 pwCF (≥12y) were recruited. The 6MWT distance increased significantly after one and two years of ETI compared with baseline (608±73 m at baseline; 636±75 m after one year of ETI, p < 0.0001; 641±71 m after two years of ETI, p < 0.0001). The number of repetitions during the 1STST enhanced significantly after one and two years of ETI compared with baseline (51±15 at baseline; 55±14 after one year of ETI, p = 0.0022; 56±14 after two years of ETI, p = 0.0042). MVCQ also showed a significant improvement after one and two years of ETI compared with baseline (69±29Nm at baseline; 76±28Nm after one year of ETI, p = 0.0015; 82±29Nm after two years of ETI, p < 0.0001) as well as between one and two years (p = 0.0139). In contrast, no significant change was observed when comparing results in 6MWT and 1STST between one and two years of ETI.

CONCLUSION

6MWT, 1STST and MVCQ improved after one year of ETI with improvements persisting at two years of treatment.