Disparities in HbA1c Levels Between African-American and Non-Hispanic White Adults With Diabetes
A meta-analysis
- Julienne K. Kirk, PHARMD, CDE1,
- Ralph B. D’Agostino, Jr., PHD2,
- Ronny A. Bell, PHD2,
- Leah V. Passmore, MS2,
- Denise E. Bonds, MD, MPH23,
- Andrew J. Karter, PHD4 and
- K.M. Venkat Narayan, MD, MPH, MBA5
- 1Family and Community Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina
- 2Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina
- 3Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina
- 4Division of Research, Kaiser Permanente, Oakland, California
- 5National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia
- Address correspondence and reprint requests to Julienne K. Kirk, PharmD, CDE, Associate Professor, Family and Community Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1084. E-mail: jkirk{at}wfubmc.edu
Abstract
OBJECTIVE—Among individuals with diabetes, a comparison of HbA1c (A1C) levels between African Americans and non-Hispanic whites was evaluated. Data sources included PubMed, Web of Science, the Cumulative Index to Nursing and Allied Health, the Cochrane Library, the Combined Health Information Database, and the Education Resources Information Center.
RESEARCH DESIGN AND METHODS—We executed a search for articles published between 1993 and 2005. Data on sample size, age, sex, A1C, geographical location, and study design were extracted. Cross-sectional data and baseline data from clinical trials and cohort studies for African Americans and non-Hispanic whites with diabetes were included. Diabetic subjects aged <18 years and those with pre-diabetes or gestational diabetes were excluded. We conducted a meta-analysis to estimate the difference in the mean values of A1C for African Americans and non-Hispanic whites.
RESULTS—A total of 391 studies were reviewed, of which 78 contained A1C data. Eleven had data on A1C for African Americans and non-Hispanic whites and met selection criteria. A meta-analysis revealed the standard effect to be 0.31 (95% CI 0.39–0.25). This standard effect correlates to an A1C difference between groups of ∼0.65%, indicating a higher A1C across studies for African Americans. Grouping studies by study type (cross-sectional or cohort), method of data collection for A1C (chart review or blood draw), and insurance status (managed care or nonmanaged care) showed similar results.
CONCLUSIONS—The higher A1C observed in this meta-analysis among African Americans compared with non-Hispanic whites may contribute to disparity in diabetes morbidity and mortality in this population.
Footnotes
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This publication was made possible through a cooperative agreement between the Centers for Disease Control and Prevention (CDC) and the Association of Teachers of Preventive Medicine (ATPM) (award no. TS-0778). Its contents are the responsibility of the authors and do not necessarily reflect the official views of CDC or ATPM.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
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- Accepted May 27, 2006.
- Received October 14, 2005.
- DIABETES CARE
