Background: This study examined the drug-specific and overall adherence of teenagers and adults with cystic fibrosis (CF) to inhaled therapies, to assess the degree of adherence, stability over a period of 4 years, and its association with health outcomes.
Methods: Fifty-five participants (30 women and 25 men) aged 14 years or older from two CF centers were enrolled in a retrospective review of inhaled medication adherence over 4 years. Adherence was assessed by the number of doses that were obtained by each participant based on the "e-prescription.gr" platform and the calculation of the medication possession ratio (MPR).
Results: The mean composite MPR (cMPR) for the entire research period was 0.75 ± 0.19. A total of 43.4% of participants showed a variance of adherence <25%. Participants with stable adherence had a significantly higher mean cMPR compared with those with variable adherence (0.86 ± 0.16 vs. 0.66 ± 0.17, p < 0.001). A statistically significant difference between groups of patients with different degrees of mean cMPR and mean weight was observed (p = 0.011). Patients with a mean cMPR ≥0.80 weighed significantly more than those with moderate and low adherence. In addition, mean weight correlated significantly with the mean cMPR (Β [95% confidence interval] = 14.845 [0.191-29.498], r = 0.269, p = 0.047).
Conclusions: In our setting, the cMPR was easy to assess and showed that adherence was probably better than expected. The association of cMPR with weight should be further investigated. Stable adherence seemed to be related to high adherence. This observation could enhance our understanding of people with CF and their approach to treatment.
Keywords: composite MPR (cMPR); health outcomes; lung function; medication possession ratio (MPR); weight.
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