Validation and reliability of the Turkish versions of the compliance questionnaire of rheumatology (CQR-19 and CQR-5) in rheumatoid arthritis patients: A cross-sectional study

ObjectiveMedication adherence is crucial for effective treatment and long-term outcomes in rheumatoid arthritis (RA). The Compliance Questionnaire of Rheumatology (CQR) is a widely used self-report tool for evaluating adherence. This study aimed to validate the Turkish versions of the CQR-19 and its short form, the CQR-5, in RA patients, in order to support the assessment of treatment adherence in this population.MethodsA cross-sectional study was conducted at a tertiary care center with patients who were diagnosed with RA according to the 2010 ACR/EULAR classification criteria and who had been receiving treatment for at least one year. Participants completed the Turkish versions of the CQR-19 and CQR-5. Objective adherence was assessed via prescription refill data and pill counts. Construct validity was evaluated using Confirmatory and Exploratory Factor Analyses. Internal consistency was assessed with Cronbach's alpha. Criterion validity was examined through correlations between CQR scores and objective adherence rates.ResultsA total of 155 participants had a mean age of 57.4 ± 12.4 years, with 87% being female. The CQR-19 showed a two-factor structure (KMO = 0.927, Bartlett's test p < 0.0001), while the CQR-5 demonstrated a unidimensional structure with good model fit. Internal consistency was high (α = 0.9248 for CQR-19; α = 0.8599 for CQR-5). CQR scores correlated significantly with objective adherence (p < 0.0001), supporting criterion validity.ConclusionsThe Turkish versions of the CQR-19 and CQR-5 are valid, reliable tools for assessing medication adherence in RA patients and suitable for use in clinical and research settings.