title: Medication adherence and racial differences in A1C control.
abstract: OBJECTIVE
  The purpose of this study was to examine medication adherence and other self-management practices as potential determinants of higher glycemic risk among black relative to white patients.
  
  
  METHODS
  We used a retrospective, longitudinal repeated-measures design to model the contribution of medication adherence to black-white differences in A1C among type 2 diabetic patients at a large multispecialty group practice. We identified 1,806 adult (aged >/=18 at diagnosis) patients (467 black and 1,339 white) with newly initiated oral hypoglycemic therapy between 1 December 1994 and 31 December 2000. Race was identified using an electronic medical record and patient self-report. Baseline was defined as the 13 months preceding and included the month of therapy initiation. All patients were required to have at least 12 months of follow-up.
  
  
  RESULTS
  At initiation of therapy, black patients had higher average A1C values compared with whites (9.8 vs. 8.9, a difference of 0.88; P < 0.0001). Blacks had lower average medication adherence during the first year of therapy (72 vs. 78%; P < 0.0001). Although more frequent medication refills were associated with lower average A1C values, adjustment for adherence did not eliminate the black-white gap.
  
  
  CONCLUSIONS
  We found persistent racial differences in A1C that were not explained by differences in medication adherence. Our findings suggest that targeting medication adherence alone is unlikely to reduce disparities in glycemic control in this setting. Further research is needed to explore possible genetic and environmental determinants of higher A1C among blacks at diagnosis, which may represent a critical period for more intensive intervention.
authors.affiliation: Ambulatory Care and Prevention, Harvard Medical School, Boston, Massachusetts, USA. aadams@hms.harvard.edu
authors.forename: Alyce S
authors.initials: AS
authors.lastname: Adams
authors.forename: Connie Mah
authors.initials: CM
authors.lastname: Trinacty
authors.forename: Fang
authors.initials: F
authors.lastname: Zhang
authors.forename: Ken
authors.initials: K
authors.lastname: Kleinman
authors.forename: Richard W
authors.initials: RW
authors.lastname: Grant
authors.forename: James B
authors.initials: JB
authors.lastname: Meigs
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Soumerai
authors.forename: Dennis
authors.initials: D
authors.lastname: Ross-Degnan
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D044383:Black People / Q000706:statistics & numerical data; D001835:Body Weight; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy / Q000523:psychology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D044469:Racial Groups / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D044465:White People / Q000706:statistics & numerical data
chemical_list: D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents