title: Factors associated with medication refill adherence in cardiovascular-related diseases: a focus on health literacy.
abstract: 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.
authors.affiliation: Emory Center on Health Outcomes and Quality, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA. jagazma@sph.emory.edu
authors.forename: Julie A
authors.initials: JA
authors.lastname: Gazmararian
authors.forename: Sunil
authors.initials: S
authors.lastname: Kripalani
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Miller
authors.forename: Katharina V
authors.initials: KV
authors.lastname: Echt
authors.forename: Junling
authors.initials: J
authors.lastname: Ren
authors.forename: Kimberly
authors.initials: K
authors.lastname: Rask
mesh_terms: 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
chemical_list: D002317:Cardiovascular Agents