Medication use in people with cystic fibrosis before and after modulator therapy

Long-term changes in medication dispensings post cystic fibrosis transmembrane conductance regulator (CFTR) modulator initiation have not been described. Our study aimed to investigate changes in medication use following the initiation of modulator therapy in people with cystic fibrosis (PwCF) in Australia.

Using a 10% sample of the Australian Pharmaceutical Benefits Scheme (PBS) data between 2013 and 2022, linear regression was used to analyse dispensings in PwCF who initiated any modulator (cases) and matched PwCF controls not dispensed a modulator. The difference in mean number of total monthly dispensings pre- and post-modulator initiation was analysed, with separate analyses by medication class.

A total of 247 cases were matched 1:1 to controls (case and control median age 21 years (IQR: 13-32), 55.1% male). Immediately after modulator initiation, the mean number of dispensings was 0.9 higher in the modulator group, but then decreased to the level of controls after approximately 5 years. After 7.5 years, cases had decreased opioids compared to the pre-modulator period (β-coefficient: -0.00131, 95% CI: -0.00164, -0.00097) whilst controls did not (β: -0.00014, 95% CI: -0.00042, 0.00014). Over the same time period controls had an increase in psychotropics (β: 0.00389, 95% CI:0.00295, 0.00484) whilst cases remained stable (β: -0.00014, 95% CI: -0.0006, 0.00031). Women's health medications increased in cases (β:0.00026, 95% CI:0.0001, 0.00042) but decreased in controls (β: 0.00044, 95% CI: 0.00063, -0.00025).

Modulator initiation in PwCF was associated with decreased dispensings of opioids and psychotropics, and increased dispensings of women's health medications, suggesting improved patient outcomes across multiple clinical domains.