Assessment of Medication Adherence and Related Factors in Children and Adolescents with Cystic Fibrosis: A Pharmacist-Led Study

Background: Medication non-adherence in cystic fibrosis (CF) can lead to reduced drug efficacy and suboptimal care. Objectives: This study aimed to evaluate adherence to commonly used medications and related factors among children and adolescents with CF. Methods: A research pharmacist assessed drug adherence using the 5-item Medication Adherence Rating Scale (MARS-5) through face-to-face interviews with patients and their parents. Based on the MARS-5 score, patients were categorized as having perfect (≥ 25) or lower (< 25) treatment adherence. Results: A total of 300 patients were included in the study. Between 42.0% and 87.9% of patients were lower-adherent in at least one aspect of their treatment. Among those who received all medications, 86.9% were lower-adherent. Specifically, 42.0% of patients had lower adherence to inhalants, 67.6% to systemic antibiotics, 81.4% to gastrointestinal agents, and 87.9% to nutritional supplements. Factors significantly associated with adherence included the number of drugs for inhalants and systemic antibiotics; the mother’s education level for inhalants, systemic antibiotics, and gastrointestinal agents; and distance from the medical center for inhalants and nutritional supplements (all P < 0.05). Conclusions: Non-adherence to inhalants, systemic antibiotics, gastrointestinal agents, and nutritional supplements is common among children and adolescents with CF. Adherence to one class of medication does not predict adherence to others. A high number of drugs, a low mother’s education level, and a long distance from the medical center decrease the likelihood of perfect adherence to CF medications.