Objectives: Medication literacy comprises the skills needed to access, understand, and act on medication information. Low medication literacy is frequent among older adults, making them more susceptible to negative health outcomes. The aim of this study was to develop and evaluate the content validity of an instrument to measure medication literacy in this population.
Method: Multistage methodological study. Items were generated according to a conceptual model and a literature review. The instrument was submitted to a panel of experts to assess item's relevance, clarity, and theoretical classification. Subsequently, the instrument was applied to the target population to assess its comprehensibility.
Results: Content Validity Index results indicated excellent agreement among experts on the instrument's relevance (0.98) and clarity (0.91). Overall agreement between experts regarding the theoretical subdimensions was moderate [Fleiss' kappa=0.57 (p = 0.00)]. Items were reported to be fully understood by most representatives of the target population. The final version of the instrument had 33 items divided into eight scenarios of medication use.
Conclusion: The instrument seems to have adequate content validity and good suitability for the target population. Therefore, it can help health professionals to identify older adults with low medication literacy, aiming to improve their medication use skills.
Keywords: Content validity; Health literacy; Instrument development.
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