Background/Purpose: Adherence to disease modifying anti-rheumatic drug (DMARD) therapy is suboptimal in patients with rheumatoid arthritis (RA).  Efficient, low-cost measures are required for optimal monitoring of medication adherence in the rheumatology clinic.  Self-report tools are the most efficient and cost-effective measures available.  Recently, a 5-item version of the Compliance Questionnaire Rheumatology (CQR5) was developed from the original 19-item version to reduce patient burden¹.  Reliability of CQR5 over time has not been evaluated, nor has its association with other factors that can impact medication taking.  In a sample of RA patients, we investigated 1) test-retest reliability of CQR5 and 2) correlation of CQR5 with psychosocial and physical factors known to influence adherence. 

Methods: RA patients (disease duration ≥ 1 yr) taking at least one DMARD were randomly selected from a rheumatology clinic database. Patients were assessed at baseline and 2 weeks. Demographic data were collected at baseline.  At each visit, medication adherence was assessed with CQR5.  Each item on the CQR5 was scored on a 4-point Likert scale (1 = strongly disagree, 4 = strongly agree).  Scores for each item were summed into a total score which varied between 0 and 20.  Higher scores indicated greater adherence.   Psychosocial measures were evaluated using 1) Beliefs about Medicines Questionnaire (BMQ)², which examines beliefs around necessity of and concern with taking medications (high scores reflect strong beliefs) and 2) RA Self-Efficacy Questionnaire (RASE)³ (high scores reflect high self-efficacy).  Physical factors were assessed using 1) multi-dimensional HAQ (MDHAQ)⁴ (high numbers indicate poor general health and worse symptoms) and 2) disease activity measured by the Composite Disease Activity Index (CDAI)⁵(high scores indicate high disease activity).  Intraclass correlation coefficients (ICC) were used to evaluate test-retest reliability of CQR5 scores measured at baseline and 2 weeks.  Bivariate correlations (Pearson’s r) were performed to determine relationships between psychosocial factors and medication adherence measured by CQR5 at baseline.

Results: 100 RA patients, [age, mean (SD) = 60.75(12.67) yrs], were recruited. In this sample, the CQR5 demonstrated excellent test-retest reliability (ICC=0.78).  Adherence measured by CQR5 had a strong positive correlation with BMQ necessity scores (r = 0.64, p<0.001) and a weak negative correlation with BMQ concerns scores (r = -0.22, p<0.05).  Correlations between the CQR5 and RASE, MDHAQ, and CDAI were negligible (r<0.17, p>0.05).    

Conclusion: The CQR5 demonstrates excellent reliability over time.  Adherence measured by the CQR5 is associated with beliefs about medicines, especially around the necessity of taking medications.  A more in-depth investigation of the CQR5, including its validation against a gold standard for measuring medication adherence, is currently underway. 

References:

1)      BMC Musculoskeletal Disorders. 2013; 14:286

2)      Psychology & Health. 1999; 14: 1

3)      Musculoskeletal Care. 2008; 49: 6

4)      Best Practice & Research. Clinical Rheumatology. 2007; 21:755

5)      Arthritis Research & Therapy. 2005; 7: R796

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/test-retest-reliability-of-the-5-item-compliance-questionnaire-rheumatology-and-factors-influencing-its-assessment-of-adherence-in-patients-with-rheumatoid-arthritis/