title: Regional, Geographic, and Ethnic Differences in Medication Adherence Among Adults with Type 2 Diabetes.
abstract: BACKGROUND
  Medication adherence, a critical component of glycemic control for patients with type 2 diabetes, differs by race/ethnicity. However, few studies have examined regional and rural/urban differences in medication adherence and whether racial/ethnic differences persist after controlling for these differences.
  
  
  OBJECTIVE
  To examine regional, rural/urban, and racial/ethnic differences in medication adherence in a national sample of veterans with type 2 diabetes.
  
  
  METHODS
  We performed a cohort study of a national sample of veterans with diabetes (N = 690,968) receiving prescriptions for insulin or oral hypoglycemic agents in 2002. Patients were followed until death, loss to follow-up, or through December 2006. We calculated the annual medication possession ratio (MPR) for each veteran across 4 groups of medication users: individuals using (1) insulin only, (2) oral hypoglycemic agents only, (3) insulin combined with hypoglycemic agents, and (4) insulin or oral hypoglycemic agents (primary analysis).
  
  
  RESULTS
  In longitudinal models for the primary analysis, adjusting for relevant covariates and time trends, MPR was significantly lower among non-Hispanic blacks (NHBs), Hispanics, and individuals with other/missing/unknown race/ethnicity (6.07%, 1.76%, and 2.83% lower, respectively) relative to non-Hispanic whites (NHWs). MPR was also 2.0% higher in rural versus urban veterans and 1.28% higher in the mid-Atlantic, 2.04% higher in the Midwest, and 0.76% lower in the West, relative to the South. There was a significant race/ethnicity and urban/rural interaction. In NHWs and NHBs, MPR was 1.91% and 2.00% higher, respectively, in rural versus urban veterans; in contrast, in Hispanics, MPR was 1.0% lower in rural veterans relative to urban veterans.
  
  
  CONCLUSIONS
  In a national longitudinal cohort of veterans with type 2 diabetes, we found significant regional, rural/urban, and racial/ethnic differences in MPR. Rural/urban residence modified the effect of race/ethnicity on MPR. Recognition of these differences can enable clinicians to better allocate resources and target quality improvement programs.
authors.affiliation: Leonard E Egede MD MS, Director, Center for Disease Prevention and Health Interventions for Diverse Populations, Ralph H. Johnson Veterans Affairs Medical Center; Division of General Internal Medicine & Geriatrics, Medical University of South Carolina; Center for Health Disparities Research, Charleston, SC egedel@musc.edu.
authors.forename: Leonard E
authors.initials: LE
authors.lastname: Egede
authors.affiliation: Mulugeta Gebregziabher PhD, Investigator, Center for Disease Prevention and Health Interventions for Diverse Populations, Ralph H. Johnson Veterans Affairs Medical Center; Division of Biostatistics & Epidemiology, Medical University of South Carolina.
authors.forename: Mulugeta
authors.initials: M
authors.lastname: Gebregziabher
authors.affiliation: Kelly J Hunt PhD, Investigator, Center for Disease Prevention and Health Interventions for Diverse Populations, Ralph H. Johnson Veterans Affairs Medical Center; Division of Biostatistics & Epidemiology, Medical University of South Carolina.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Hunt
authors.affiliation: Robert N Axon MD MSCR, Investigator, Center for Disease Prevention and Health Interventions for Diverse Populations, Ralph H. Johnson Veterans Affairs Medical Center; Division of General Internal Medicine & Geriatrics, Medical University of South Carolina.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Axon
authors.affiliation: Carrae Echols MS, Statistician, Center for Disease Prevention and Health Interventions for Diverse Populations, Ralph H. Johnson Veterans Affairs Medical Center.
authors.forename: Carrae
authors.initials: C
authors.lastname: Echols
authors.affiliation: Gregory E Gilbert MSPH, Statistician, Center for Disease Prevention and Health Interventions for Diverse Populations, Ralph H. Johnson Veterans Affairs Medical Center.
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Gilbert
authors.affiliation: Patrick D Mauldin PhD, Investigator, Center for Disease Prevention and Health Interventions for Diverse Populations, Ralph H. Johnson Veterans Affairs Medical Center; Department of Clinical Pharmacy and Outcome Sciences, South Carolina College of Pharmacy, Charleston.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Mauldin
mesh_terms: D000284:Administration, Oral; D000328:Adult; D044383:Black People; D001786:Blood Glucose; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004359:Drug Therapy, Combination; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D007328:Insulin / Q000008:administration & dosage; D008297:Male; D055118:Medication Adherence / Q000208:ethnology; D008875:Middle Aged; D012424:Rural Population; D014505:Urban Population; D014728:Veterans; D044465:White People; D016903:Drug Monitoring
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin