Validity and reliability of Medication Adherence Report Scale (MARS-5) in a Southeastern European population

Medication adherence improves health outcomes and overall well-being. Questionnaires and reporting scales remain the most accessible and cost-effective assessment tools for adherence; however, they must demonstrate validity, reliability, and sensitivity to change. The aim of this study is to assess the validity and reliability of the Medication Adherence Report Scale (MARS-5) in the adult population of Albania and to examine the correlations between the adjusted summary scores of MARS-5 and the sociodemographic and health status characteristics of the study population.

A cross-sectional study was conducted in Albania during November-December 2024, including a sample of 256 individuals ≥18 years with hypertension, diabetes, or both conditions. The Albanian version of MARS-5 translated, according to guidelines, was administered twice (over two weeks) in-person to patients visiting primary health care settings (≈56% females; response: ≈85%). Participants also reported on sociodemographic factors and health status characteristics. Cronbach's alpha was used to measure internal consistency and Pearson's correlation coefficient for the assessment of test-retest reliability.

Cronbach's alpha was 0.89 for the test and 0.91 for the retest. Test-retest reliability was high (r = 0.95, P < 0.001). Above median scores of adherence (adjusted summary score: > 4) were positively associated with urban residence, higher educational attainment, a higher income level, and periodic medical check-ups, but inversely related to duration of hypertension, number of medications for hypertension, overall number of medications, number of times per day using medications, and the total number of daily doses of medications.

MARS-5 is a valid and reliable tool for assessing medication adherence in the adult population of Albania.