Health Literacy and Adherence to Medical Treatment in Chronic and Acute Illness: A Meta-Analysis

Abstract

Objective

To use meta-analytic techniques to assess average effect sizes in studies of: (1) the correlation between patient health literacy and both medication and non-medication adherence, and (2) the efficacy of health literacy interventions on improving health literacy and treatment adherence.

Methods

PsychINFO and PubMed databases were searched (1948–2012). A total of 220 published articles met the criteria for inclusion; effect sizes were extracted and articles were coded for moderators.

Results

Health literacy was positively associated with adherence ( r= .14), and this association was significantly higher among non-medication regimens and in samples with cardiovascular disease. Health literacy interventions increased both health literacy ( r = .22) and adherence outcomes ( r= .16). Moderator analyses revealed greater intervention efficacy when health literacy and adherence were assessed using subjective measures compared to objective measures. Health literacy interventions had a greater effect on adherence in samples of lower income and of racial-ethnic minority patients than in non-minority and higher income samples.

Conclusion

This is the first study to synthesize both correlational and intervention studies examining the relationship between health literacy and adherence to both medication and non-medication regimens.

Implications

These findings demonstrate the importance of health literacy and the efficacy of health literacy interventions especially among more vulnerable patient groups.