Background: Cystic fibrosis (CF) is a progressive disease caused by a mutation in the CF transmembrane conductance regulator (CFTR) gene producing a dysfunctional CFTR protein. A new combination drug, elexacaftor-tezacaftor-ivacaftor (ETI), remarkably slows associated lung disease but has been associated with substantial weight gain.
Methods: We reviewed charts of patients with weight measurements before and after starting ETI. We explored clinical variables potentially predicting weight gain at 3 and 6 months post-starting ETI using linear regression modeling of CFTR modulator starting age, gender, FEV1, mutation type, pancreatic sufficiency, HgbA1c, prior modulator use, numbers of lung exacerbations in the year prior to starting ETI and year post starting ETI as input variables.
Results: Multivariable linear regression for BMI change after six months of treatment shows strong associations with age and number of prior pulmonary exacerbations. For every year increase in age, BMI decreased by 0.04 six months after starting ETI (95% Confidence Interval [CI] = 0.935-0.979, p < 0.001). Each additional exacerbation in the year prior to starting ETI was associated with a BMI change of 0.39 (CI = 1.17-1.65, p=0.002).
Conclusions: Young patients with many exacerbations in the year prior to starting ETI may gain more weight over the months following initiation of ETI than older patients with fewer prior exacerbations.
Acknowledgements: This project was supported by the CF Foundation (CFF) (CC132-16AD), the Ben B and Iris M Margolis Foundation of Utah and the Claudia Ruth Goodrich Stevens Endowment Fund at the University of Utah.
