Development and validation of a self-report measure of practical barriers to medication adherence: The medication practical barriers to adherence questionnaire (MPRAQ)

Aim: This study reports the development and validation of a new self-report measure, the Medication Practical barriers to Adherence Questionnaire (MPRAQ), which assesses practical barriers to medication adherence.

Methods: The MPRAQ comprises 15 statements describing practical barriers. Responses are scored on a 5-point Likert scale; higher scores indicate more practical barriers. Initial face validity was evaluated by cognitive testing with patients from a diabetes support group. Following refinement, internal reliability and construct validity were assessed in two samples: patients recruited via Amazon mTurk and the Nivel Dutch Healthcare Consumer Panel (COPA). Respondents completed the Beliefs about Medicines Questionnaire (BMQ-General and BMQ-Specific), and the Medication Adherence Report Scale (MARS-5). The mTurk sample also completed the Perceived Sensitivity to Medicines questionnaire (PSM) and repeated the MPRAQ 2 weeks later to assess test-retest reliability.

Results: Face validity was evaluated in 15 patients (46% female; mean (SD) age 64 (12) years). A total of 184 mTurk participants completed the questionnaire (in English) and 334 in COPA (in Dutch). Internal reliability was acceptable (mTurk α = 0.89; COPA α = 0.94). Construct validity was confirmed, with significant correlation between the MPRAQ and BMQ-Specific Concerns (mTurk r = 0.546, P < .0001; COPA r = 0.370, P < .0001), BMQ-General Harm (mTurk r = 0.504, P < 0.0001; COPA r = 0.219, P < .0001), BMQ-General Overuse (mTurk r = 0.324, P < .0001; COPA r = 0.109, P = .047) and PSM (mTurk only r = 0.463, P < .0001), and a negative correlation with MARS-5 (mTurk r = -0.450, P < .0001; COPA r = -0.260, P < .0001). MPRAQ did not correlate with BMQ-Specific Necessity or BMQ-General Benefit. Correlation between MPRAQ baseline and 2-week follow-up scores confirmed test-retest reliability (r = 0.745, P < .0001; n = 52).

Conclusion: MPRAQ is a reliable and valid self-report measure of practical adherence barriers.