CF Medication Utilization and Lung Function
As prior data has suggested that discontinuation of Dorn or HTS may not
alter lung function in PwCF on ETI, we examined relationships between
changes in lung function (slope ppFEV1) and changes in
MPR for various medications. Among 112 PwCF with sufficient lung
function data pre- and post-ETI, average ppFEV1increased significantly in the post-ETI period (74.5±24.4% pre-ETI,
82.6±25.0% post-ETI, p<0.001). In the pre-ETI period, lung
function declined slowly over time (slope ppFEV1 ‐0.8 ± 5.0%/year). In
the post-ETI period, change in FEV1 over time remained negative (slope
ppFEV1 ‐1.5 ± 6.1%/year) and was not statistically distinguishable from
the pre-ETI period (p=0.34). While continued decline in lung function
could reflect changes in adherence to inhaled medications, PwCF who had
lung function decline post ETI (negative ppFEV1 slopes)
had similar MPRs for Dorn and HTS to those with preserved or improving
lung function (positive slopes) (Fig 1B ). As an alternative
analysis, ppFEV1 slope did not correlate with changes in
MPR for Dorn or HTS (Fig. 1C ). To account for possible
confounding factors, we performed a multivariate analysis including age,
initial ppFEV1, and prior modulator use in the model
along with changes in MPR for Dorn and HTS. Although age at start of ETI
was correlated with slope ppFEV1 post-ETI (r=0.4,
p=0.02) in univariate analysis, no variables were significantly
correlated in multivariate analysis.