Medication Literacy Test for Older Adults: psychometric analysis and standardization of the new instrument.

BACKGROUND: Low medication literacy is prevalent among older adults and is associated with adverse drug events. The Medication Literacy Test for Older Adults (TELUMI) was developed and content validated in a previously published study. AIM: To evaluate the psychometric properties and provide norms for TELUMI scores. METHOD: This was a cross-sectional methodological study with older adults selected from the community and from two outpatient services. Descriptive item-analysis, exploratory factor analysis (EFA), item response theory (IRT), reliability, and validity analysis with schooling and health literacy were performed to test the psychometric properties of the TELUMI. The classification of the TELUMI scores was performed using percentile norms. RESULTS: A total of 344 participants, with a mean age of 68.7 years (standard deviation = 6.7), were included; most were female (66.6%), black/brown (61.8%), had low schooling level (60.2%) and low income (55.2%). The EFA pointed to the one-dimensional structure of TELUMI. A three-parameter logistic model was adopted for IRT. All items had an adequate difficulty index. One item had discrimination < 0.65, and three items had an unacceptable guessing index (< 0.35) and were excluded. The 29-item version of TELUMI had excellent internal consistency (KR20 = 0.89). There was a positive and strong association between TELUMI scores and health literacy and education level. The scores were classified as inadequate medication literacy (≤ 10.0 points), medium medication literacy (11-20 points), and adequate medication literacy (≥ 21 points). CONCLUSION: The results suggest that the 29-item version of TELUMI is psychometrically adequate for measuring medication literacy in older adults.

Medication literacy: A conceptual model.

BACKGROUND: Medication literacy reflects the specific literacy skills necessary to act on medication-related information. A comprehensive and clear conceptual model that reflects medication literacy is lacking. Conceptual models describe the components that represent a construct, allowing for its understanding and providing a rationale for its measurement. OBJECTIVES: To propose a conceptual model to support the development of an instrument to measure medication literacy. METHODS: This is a three-phase methodological study. A literature review was conducted to identify the components that should be part of the preliminary conceptual model. Subsequently, the importance of its components was judged on a Likert-5 scale. Then, the model was refined, and the dimensions and subdimensions of medication literacy were defined. RESULTS: Forty-five experts were included, with a mean age of 39.9 (SD = 10.5) years, most of them females (86.7%) and pharmacists (80%). All components of the preliminary conceptual model were considered important to extremely important by most experts. "Dosing information", "medication name", and "processing the information received about their medication and acting upon medication instructions" were the components considered most important. In the refinement phase, we identified that the construct has four dimensions - functional literacy, communicative literacy, critical literacy, and numeracy, which include the subdimensions to access, understand, evaluate, calculate, and communicate medication-related information. CONCLUSIONS: The conceptual model allowed identifying the components that represent medication literacy, which will support the development of an instrument for measuring the construct in Brazil.