PT - JOURNAL ARTICLE AU - Hansen, Carina M.E. AU - Breukelman, Anna J. AU - van den Bemt, Patricia M.L.A. AU - Zwitserloot, Annelies M. AU - van Dijk, Liset AU - van Boven, Job F.M. TI - Medication adherence to CFTR modulators in patients with cystic fibrosis: a systematic review AID - 10.1183/16000617.0060-2024 DP - 2024 Jul 01 TA - European Respiratory Review PG - 240060 VI - 33 IP - 173 4099 - http://err.ersjournals.com/content/33/173/240060.short 4100 - http://err.ersjournals.com/content/33/173/240060.full SO - EUROPEAN RESPIRATORY REVIEW2024 Jul 01; 33 AB - Background In the last decade, a fundamental shift in the treatment of cystic fibrosis (CF) took place due to the introduction of CF transmembrane conductance regulator (CFTR) modulators. Adequate medication adherence is a prerequisite for their effectiveness, but little is known about adherence to CFTR modulators. We aimed to assess the extent of medication adherence to CFTR modulators in patients with CF and assess which characteristics are associated with adherence.Methods A systematic review following PRISMA guidelines was performed. Studies needed to report adherence to CFTR modulators. Main outcomes were: 1) level of medication adherence and 2) associations of demographic and/or clinical characteristics with adherence.Results In total, 4082 articles were screened and 21 full-text papers were assessed for eligibility. Ultimately, seven studies were included. Most studies were retrospective and focused on adherence to ivacaftor or lumacaftor–ivacaftor with only one focusing on elexacaftor–tezacaftor–ivacaftor. The majority used pharmacy refill data with adherence determined with the proportion of days covered (PDC) or the medication possession ratio (MPR). One study additionally used electronic monitoring and patient self-reported adherence. Adherence was 0.62–0.99 based on pharmacy data (PDC or MPR), 61% via electronic monitoring and 100% via self-report. Age <18 years appeared to be associated with good adherence, as was a higher lung function.Conclusions Despite the wide variety of adherence methods used, adherence to CFTR modulators is suboptimal, based on objective measures such as pharmacy refill data or electronic monitoring. CFTR modulator adherence measurement and definitions requires more standardisation with a preference for objective and granular methods.Adherence to CFTR modulators ranged from 62% to 100%. This broad range may be caused by the different measurement strategies and more specifically by the different CFTR modulators. Larger studies with ETI and with standardised measurements are needed. https://bit.ly/4cjQ25y