[Evaluation of the psychometric properties of the 8-item Morisky medication adherence scale (MMAS-8) for oral anticoagulants in the Spanish population].

Abstract

Aim: The use of oral anticoagulants has increased due to the rising prevalence of auricular fibrillation, a condition that raises the risk of thromboembolic events. These drugs are effective in preventing such events, but their success depends on therapeutic adherence, which requires validated tools for assessment. The aim of this study is to evaluate the suitability of the Morisky Medication Adherence Scale-8 (MMAS-8) questionnaire in its adapted version for the Spanish population.

Materials and methods: An observational, descriptive, cross-sectional study was conducted in health centres in Jávea and Pego between 2017 and 2022. A total of 211 patients treated with oral anticoagulants for at least 6months participated. To assess adherence, the Spanish version of the MMAS-8 questionnaire was used. Reliability was determined using McDonald's Omega coefficient and the test-retest method, while validity was assessed through factor analysis.

Results: The Omega coefficient of 0.69 indicated moderate internal consistency. Items 1 and 8 showed moderate agreement, while the other items demonstrated weak agreement, resulting in overall moderate concordance. Construct validity analysis showed little variability, suggesting that the scale does not clearly reflect a unidimensional structure.

Conclusions: The MMAS-8 scale demonstrated moderate internal consistency and low temporal stability. Furthermore, the results suggest that the scale is not suitable for measuring adherence in patients treated with oral anticoagulants due to its lack of robustness in the studied population.