Systematic review of consistency between adherence to cardiovascular or diabetes medication and health literacy in older adults.
OBJECTIVE
To review the relationship between health literacy and adherence to cardiovascular/diabetes medication.


METHODS
We searched EMBASE (1974-February 2012) and MEDLINE (1948-February 2012). Search terms included health literacy, numeracy, health education and related terms, health literacy measurement tools, and medication adherence.


METHODS
English-language articles of all study designs were considered. Articles were included if they had a measurement of health literacy and medication adherence and if participants were older adults taking drugs for cardiovascular illness or diabetes mellitus.


RESULTS
A total of 1310 citations were reviewed, including 9 articles that reported on 7 research studies. Most studies were retrospective, and all were based in the US. Because there was considerable diversity in measurements, participant characteristics, and outcome measures, we conducted a narrative synthesis rather than a meta-analysis. In assessing study validity, we looked at participant selection, method of measuring health literacy and medication adherence, missing data or losses, and adjustment for confounders. Of the 7 included studies, only 1 found a demonstrable association between health literacy and refill adherence. One clinical trial failed to show significant improvements in medication adherence after an intervention to improve health literacy.


CONCLUSIONS
The current evidence does not show a definite association between health literacy and medication adherence in older adults with cardiovascular disease or diabetes mellitus. In the absence of a definite link, efforts to develop interventions to improve health literacy would not necessarily improve adherence to cardiovascular medications. There is an urgent need for robust studies outside of the US, with wider, generalized recruitment of participants.
Norwich Medical School, University of East Anglia, Norwich, UK. y.loke@uea.ac.uk
Yoon K
YK
Loke
Ina
I
Hinz
Xia
X
Wang
Charlotte
C
Salter
D002317:Cardiovascular Agents / Q000008:administration & dosage*; D002318:Cardiovascular Diseases / Q000188:drug therapy; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy; D057220:Health Literacy; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D055118:Medication Adherence; D012646:Self Administration
D002317:Cardiovascular Agents; D007004:Hypoglycemic Agents