Effects of an Exercise Intervention on Exercise Capacity in Adults With Cystic Fibrosis: A Quasi-Experimental Study Comparing Individuals Treated With and Without Elexacaftor/Tezacaftor/Ivacaftor.

Abstract

Background: The effects of CFTR modulators, particularly elexacaftor/tezacaftor/ivacaftor (ETI), on exercise capacity in people with cystic fibrosis (pwCF) remain unclear, with no data available on their impact within the context of an exercise intervention. Therefore, this study aimed to assess the effects of an exercise intervention on exercise capacity in adults with CF, comparing those treated with and without ETI.

Methods: A total of 56 adult pwCF participated in this quasi-experimental study as part of a rehabilitation program, which included a 3.5-week exercise intervention. The program involved five weekly 45-min sessions, including endurance training on a cycle ergometer. VO_{2 peak} and W_peak were the primary outcomes used to assess changes in exercise capacity.

Results: The intervention significantly increased VO_{2 peak} and W_peak in all pwCF, regardless of ETI use, with similar improvements between groups. PwCF with lower baseline fitness (VO_{2 peak} ≤ 81%pred) showed greater improvements than those with higher fitness (VO_{2 peak} ≥ 82%pred). ppFEV1 remained unchanged, while BMI increased in both groups. Notably, the ETI group spent significantly more time in physical activity (PA) at hard and very hard intensities compared to the non-ETI group. Additionally, a positive correlation was observed between PA intensity and VO_{2 peak} and W_peak in the ETI group.

Conclusion: Independent of ETI treatment, adult pwCF improve their exercise capacity by participating in a regular exercise program. ETI treatment appears to enhance time spent in higher PA intensities. Despite the effectiveness of CFTR modulators, regular PA and exercise remain essential to maintain and improve exercise capacity in pwCF.