Objective: Although cross-sectional studies have demonstrated poor adherence to airway clearance therapy (ACT) for patients with cystic fibrosis (CF), no studies have identified longitudinal patterns of adherence. The objective was to characterize and identify predictors of ACT adherence trajectories for individuals with CF.
Methods: Secondary data analyses were conducted for a randomized clinical trial examining differences in three ACTs. Participants (n = 153; M = 14.3 years, 55% male, 86% Caucasian, baseline FEV(1)% predicted: M = 86.7)/primary caregivers completed Daily Phone Diaries, an empirically supported adherence measure, every 4 months.
Results: Group-based trajectory modeling revealed the best-fitting solution was a three-group model: low-adherence (14%), medium-adherence (49%), and high-adherence (37%) groups. ACT type was the only significant predictor of adherence trajectories.
Discussion: Three trajectories of adherence to ACT for patients with CF were found. With the identification of trajectories, adherence interventions can be targeted for the subgroup at highest risk in order to prevent poor health outcomes.