One year effect of tezacaftor and ivacaftor on functional exercise capacity and muscle strength in people with cystic fibrosis

Background: The 1-min sit-to-stand test (1STST) is a practical tool to evaluate physical capacity. The aim of this study was to assess the impact of tezacaftor and ivacaftor on functional exercise capacity, muscle strength and symptoms in people with cystic fibrosis (PwCF). Methods: The assessments were performed during the first year of tezacaftor and ivacaftor using the 1STST, 6-min walk test (6MWT), MicroFET2 dynamometer®, CF Questionnaire-Revised (CFQ-R), Leicester Cough Questionnaire (LCQ). Forced expiratory volume in 1 s (FEV1), body mass index (BMI), pancreatic sufficiency status, genotype and microbiologic data were also collected. Results: Fifty-four PwCF participated to the study and took at least one dose of tezacaftor-ivacaftor. Mean age was 26y±10 (±SD), median BMI 20.9 kg/m2 (interquartile range) (19.4; 23.5) and mean FEV1 82 percent of predicted values (%PV) ± 21. Significant correlations were found at baseline between the 1STST and the 6MWT (r = 0.617, p