Ideal instruments used to measure health literacy related to medication use: A systematic review.

BACKGROUND

Prior studies showed the association between inadequate health literacy (HL) and poor medication-related skills, while none of the published studies have reviewed and compared the existing instruments used to measure medication-related HL. This systematic review comprehensively summarizes the existing instruments that assess medication-related HL.

OBJECTIVES

To identify appropriate HL instruments related to medication use as screening tools for enhancing patients' ability to use medications correctly.

METHODS

This review retrieved medication-related HL instruments that were published between 2000 and 2019 from three databases (i.e., PubMed, Scopus, EMBASE) and by hand-searching. The PRISMA procedure was followed as well as the SURGE guideline to assess the quality of studies. Psychometric properties, HL dimensions, and types of medication information gleaned from the items in three types of HL instruments (i.e., general, disease-specific, medication-specific) were compared to identify appropriate medication-related HL instruments.

RESULT: Forty-eight instruments were identified from 44 studies, whereas 70.8% instruments were either disease- or medication-specific HL instruments. Most instruments with different sample sizes showed certain an extent of reliability and validity. The distributions of HL dimensions and types of medication information among the relevant items were varied across different types of instruments. The five instruments (named as the 16SQ, AKQ-CQ, DHLKI, AKT, and ChMLM) were identified as the most appropriate instruments for three types of medication-related HL, respectively. These appropriate instruments consistently covered items related to HL dimensions of literacy and comprehension and medication-related information regarding dosing, treatment indication, and side effects/precautions.

CONCLUSION

Of 48 identified instruments mainly derived from disease- or medication-specific studies, the five most appropriate medication-related HL instruments were identified to support clinicians in facilitating patients' correct medication use. Further confirmation to explore the usefulness among these instruments are needed.