Criterion validity of 14-item Health Literacy Scale (HLS-14) questionnaire in Brazilian adults and older people

The objective of this study was to evaluate the criterion validity of the 14-item Health Literacy Scale (HLS-14) in Brazilian adults and older adults. The cross-sectional study performed in an oral health (OH) prospective cohort was conducted in 2017 in Piracicaba, Brazil. The HLS-14 questionnaire was applied to evaluate Health Literacy (HL) by dimensions: Functional literacy (FunL), Communicative literacy (ComL) and Critical literacy (CriL). An evaluation protocol (EP) was proposed to evaluate the criterion validity of HLS-14 considering HL dimensions (FunL: reading of the drug information leaflets; ComL: reading of the medical prescription and CriL: identification of OH conditions). HL (total) was dichotomized by the median in high (≥35 point) or low (<35 point) HL. Kendall's rank correlation coefficient (p < 0.05) and chi-squared test (p < 0.05) were applied. There was agreement between EP and HLS-14 for FunL (p < 0.01). There was association between high HL, measured through the HLS-14 questionnaire, assessing the reading of the drug information leaflets (p < 0.01) and the need for help to read them (p < 0.01). EP showed association between high HL and being able to read the drug information leaflet (p < 0.01), not needing help to read (p < 0.01), having found in the prescription all the information to take the medicine (p < 0.01) and knowing two or more health and OH information in the educational material (p < 0.01). The HSL-14 questionnaire showed criterion validity to measure FunL, and for some items of ComL and CriL evaluation. HL evaluation in a practical and multidimensional way could have an effect on the communication between health professional and patient, motivation and health outcomes.