Validation of the Treatment Satisfaction Questionnaire for Medication in patients with cystic fibrosis

BackgroundOur objective was to confirm the measurement properties of the Treatment Satisfaction Questionnaire with Medication (TQSM) in patients with cystic fibrosis (CF) receiving inhaled antibiotics.MethodsThe TSQM was included in the EAGER study, a clinical trial comparing a nebulized and a dry powder device for inhaled tobramycin in a CF population with chronic Pseudomonas aeruginosa (Pa) lung infection, aged 6 years and above (N = 553). Reliability and validity of the questionnaire were investigated using Cronbach's α and multitrait–multimethod approach.ResultsThe TSQM demonstrated very good reliability and construct validity: all Cronbach's α were above 0.86 and all items met the convergent and discriminant validity criteria. In multivariate regressions, higher patient satisfaction and lower perceived impact of side-effects were associated with better treatment compliance.ConclusionsThe TSQM showed very good measurement properties that strongly support its use to assess satisfaction of patients with CF taking inhaled antibiotics.