Mechanisms for racial and ethnic disparities in glycemic control in middle-aged and older Americans in the health and retirement study.
BACKGROUND
Mechanisms for racial/ethnic disparities in glycemic control are poorly understood.


METHODS
A nationally representative sample of 1901 respondents 55 years or older with diabetes mellitus completed a mailed survey in 2003; 1233 respondents completed valid at-home hemoglobin A(1c) (HbA(1c)) kits. We constructed multivariate regression models with survey weights to examine racial/ethnic differences in HbA(1c) control and to explore the association of HbA(1c) level with sociodemographic and clinical factors, access to and quality of diabetes health care, and self-management behaviors and attitudes.


RESULTS
There were no significant racial/ethnic differences in HbA(1c) levels in respondents not taking antihyperglycemic medications. In 1034 respondents taking medications, the mean HbA(1c) value (expressed as percentage of total hemoglobin) was 8.07% in black respondents and 8.14% in Latino respondents compared with 7.22% in white respondents (P < .001). Black respondents had worse medication adherence than white respondents, and Latino respondents had more diabetes-specific emotional distress (P < .001). Adjusting for hypothesized mechanisms accounted for 14.0% of the higher HbA(1c) levels in black respondents and 19.0% in Latinos, with the full model explaining 22.0% of the variance. Besides black and Latino ethnicity, only insulin use (P < .001), age younger than 65 years (P = .007), longer diabetes duration (P = .004), and lower self-reported medication adherence (P = .04) were independently associated with higher HbA(1c) levels.


CONCLUSIONS
Latino and African American respondents had worse glycemic control than white respondents. Socioeconomic, clinical, health care, and self-management measures explained approximately a fifth of the HbA(1c) differences. One potentially modifiable factor for which there were racial disparities--medication adherence--was among the most significant independent predictors of glycemic control.
Heisler
Michele
M
Veterans Affairs Center for Practice Management and Outcome Research, Veterans Affairs Ann Arbor Healthcare Systems, MI 48113-0170, USA. mheisler@umich.edu
Faul
Jessica D
JD
Hayward
Rodney A
RA
Langa
Kenneth M
KM
Blaum
Caroline
C
Weir
David
D
D000368:Aged; D000369:Aged, 80 and over; D044383:Black People; D003920:Diabetes Mellitus / Q000097:blood / Q000208:ethnology*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006297:Health Services Accessibility / Q000706:statistics & numerical data*; D006630:Hispanic or Latino; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance / Q000208:ethnology*; D012959:Socioeconomic Factors; D016312:Treatment Refusal / Q000208:ethnology*; D014481:United States / Q000453:epidemiology; D044465:White People; D001741:Black or African American
D006442:Glycated Hemoglobin