Weight a Minute: Exploring the Effect on Weight and Body Composition After the Initiation of Elexacaftor/tezacaftor/ivacaftor in Adults with CF

Background: Life expectancy for people with CF (PwCF) continues to increase. However, a trend of overweight and obesity is emerging along with concern of developing comorbitities. Body composition (BC) is associated with several health indices. However, body mass index (BMI) does not provide information on BC.

Methods: BMI, fat mass (FM), fat free mass (FFM), using bioelectrical impedance, lung function and sweat chloride (SwCl) were assessed in adult PwCF in routine clinic before and after commencement of the CFTR modulator Elexacaftor/Tezacaftor/Ivacaftor.

Results: 109 PwCF (76 male) underwent assessments at both time points. In all PwCF a significant upward trend in BMI was observed (p < 0.001). Males significantly gained more FFM compared to females (p0.03), whilst prevalence of normal weight obesity increased primarily in females (25-38%).

Conclusion: Routine BC assessment identifies individuals with elevated FM or depleted FFM enabling individualised care with the focus of optimising BC.