Assessment of long-term medication adherence with cystic fibrosis: An integrated approach

Cystic fibrosis (CF) is a genetic disorder that creates a multisystem pathology resulting in complex treatment regimens. In 2014, 43% of people with CF at an academic medical center experienced medication acquisition barriers. The creation of an integrated specialty pharmacy with an embedded CF team pharmacist was launched in 2016. In addition to filling specialty medications, this specialty pharmacy filled all patient medications through a service called total care pharmacy (TCP). This service was hypothesized to positively impact medication adherence.

Adherence analysis was performed by utilizing the proportion of days covered (PDC). PDC was analyzed during years 1, 2, and 3 of therapy. PDC was calculated for medications with at least three fills during each year. Patients with PDC less than 80% were considered nonadherent and underwent manual chart review to identify a documented reason for nonadherence.

Patients in the first year of dornase alfa therapy had significantly higher adherence in the TCP cohort compared to non-TCP (81.3% PDC vs. 66.0%; p = .006), which was largely driven by adult patients (73.3% vs. 56.5% for pediatric). Analysis of other medications and groups did not yield statistically significant differences. Many patients who had been classified as nonadherent had valid clinical reasons that explained gaps in therapy.

When filling medications at a specialty pharmacy integrated within the academic medication center, dornase alfa adherence was higher in the TCP group. Further studies comparing TCP with services offered by pharmacies external to the health system would better characterize the impact of TCP services.