Factors associated with medication refill adherence in cardiovascular-related diseases: a focus on health literacy.
BACKGROUND
The factors influencing medication adherence have not been fully elucidated. Inadequate health literacy skills may impair comprehension of medical care instructions, and thereby reduce medication adherence.


OBJECTIVE
To examine the relationship between health literacy and medication refill adherence among Medicare managed care enrollees with cardiovascular-related conditions.


METHODS
Prospective cohort study.


METHODS
New Medicare enrollees from 4 managed care plans who completed an in-person survey and were identified through administrative data as having coronary heart disease, hypertension, diabetes mellitus, and/or hyperlipidemia (n=1,549).


METHODS
Health literacy was determined using the short form of the Test of Functional Health Literacy in Adults (S-TOFHLA). Prospective administrative data were used to calculate the cumulative medication gap (CMG), a valid measure of medication refill adherence, over a 1-year period. Low adherence was defined as CMG> or =20%.


RESULTS
Overall, 40% of the enrollees had low refill adherence. Bivariate analyses indicated that health literacy, race/ethnicity, education, and regimen complexity were each related to medication refill adherence (P<.05). In unadjusted analysis, those with inadequate health literacy skills had increased odds (odds ratio [OR]=1.37, 95% confidence interval [CI]: 1.08 to 1.74) of low refill adherence compared with those with adequate health literacy skills. However, the OR for inadequate health literacy and low refill adherence was not statistically significant in multivariate analyses (OR=1.23, 95% CI: 0.92 to 1.64).


CONCLUSIONS
The present study suggests, but did not conclusively demonstrate, that low health literacy predicts poor refill adherence. Given the prevalence of both conditions, future research should continue to examine this important potential association.
Gazmararian
Julie A
JA
Emory Center on Health Outcomes and Quality, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA. jagazma@sph.emory.edu
Kripalani
Sunil
S
Miller
Michael J
MJ
Echt
Katharina V
KV
Ren
Junling
J
Rask
Kimberly
K
D000368:Aged; D000369:Aged, 80 and over; D002317:Cardiovascular Agents / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000188:drug therapy* / Q000517:prevention & control*; D015331:Cohort Studies; D011307:Drug Prescriptions; D004522:Educational Status; D005260:Female; D006266:Health Education; D006801:Humans; D008297:Male; D008329:Managed Care Programs; D006278:Medicare; D015233:Models, Statistical; D010349:Patient Compliance / Q000706:statistics & numerical data; D011446:Prospective Studies
D002317:Cardiovascular Agents