Validated Instruments for Measuring Health Literacy Among Traditional, Complementary, and Integrative Medicine Users: A Critical, Systematic Review

Introduction: There is a need to better understand traditional, complementary, and integrative medicine (TCIM) and health literacy (HL) as intersecting fields of research, and to identify the impact of HL on TCIM use and practices. This is best achieved through validated instruments that measure TCIM-specific HL. Methods: This critical, systematic review aimed to identify the use and features of validated instruments for measuring HL in the general adult population using TCIM, and the degree to which those elements measure TCIM-specific HL. Evaluation of the methodological rigor of instrument testing and grade determination was undertaken using the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) checklist and an adapted version of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses–COSMIN manual for the systematic review of patient-reported outcome measures. Results: A total of 21 validated HL instruments, identified from 29 studies, were included in the review. Ten instruments were specific or partially specific to TCIM. Most instruments assessed two or more HL domains ( n = 14), including five that assessed all four domains of the integrated conceptual model of HL. Approximately one quarter of all instruments received an overall assessment rating of “very good” quality ( n = 5), with majority of instruments rating as either “doubtful” ( n = 9) or “inadequate” ( n = 7) quality. Conclusion: The examination of HL in relation to TCIM use and users will clearly benefit the TCIM research field and the wider health research community. Focused efforts to develop validated TCIM-specific HL instruments will ensure TCIM use and users are not excluded from HL scholarship and advancements.