Effect of CFTR modulators on exercise tolerance and hand grip strength in CF children

Abstract

<b>Introduction:</b> Exercise capacity in CF is determined by both lung health and nutritional status. It can be quantified with the hand grip strength (HGS) test and the standardised 3 minute step test (3MST). HGS for example is indicative of lean body mass, which correlates well with lung function. Limited data in children is available on changes in exercise tolerance in CF children after starting CFTR modulators. <b>Aims:</b> To study changes in exercise capacity and HGS in children on CFTR modulators <b>Methods:</b> CF children ≥6 years eligible for Orkambi/Symkevi performed the 3MST and HGS using a digital hand dynamometer, at baseline and 6-8 months after treatment initiation. Subjective and objective assessments of breathlessness (BORG scale and 15 count score) and muscle fatigue(VAS) were performed. <b>Results:</b> 5 children(mean age 8.4 yrs +/- 1.3) started Orkambi and 8 adolescents (mean age 15.9 yrs +/- 1.7) started Symkevi. Borg scale and 15-count score improved on Orkambi. Children on Symkevi showed improved VAS (Table). These parameters did not reach statistical significance, likely due to small numbers. The median HGS and BMI improved on both CFTR modulators and improved HGS on Symkevi was statistically significant (Table). <b>Conclusion:</b> Improvement in 3MST parameters and HGS in our paediatric CF cohort suggests improved exercise capacity and fitness following CFTR modulator treatment. 3MST and HGS can be used to monitor the benefits of CFTR modulators.