Source: Williams LK. J Clin Endocrinol Metab. 2014;doi:10.1210/jc.2014-1539.
June 18, 2014
2 min read

Metformin appears to control blood glucose better in black patients

Source: Williams LK. J Clin Endocrinol Metab. 2014;doi:10.1210/jc.2014-1539.
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Black patients appear to have a better glycemic response to metformin than white patients, according to research published in The Journal of Clinical Endocrinology & Metabolism.

The variable efficacy of the first-line treatment for type 2 diabetes observed in a study at the Henry Ford Health System in Detroit requires further research to determine corresponding reductions of the disease in this population that is disproportionately burdened by diabetes, according to researchers.

“Ours is the first study to specifically assess whether metformin is effective at reducing blood glucose levels in African-American individuals,” L. Keoki Williams, MD, MPH, of the Center for Health Policy and Health Services Research at Henry Ford, told Endocrine Today. “We showed that metformin appears to be consistently more effective at reducing HbA1c levels in African Americans when compared with white individuals.”

L. Keoki Williams, MD, MPH

L. Keoki Williams

Using electronic health records, Williams and colleagues examined blood glucose control in 7,429 black and 8,783 white patients with diabetes who were prescribed metformin between 1997 and 2013. Patients had at least two HbA1c measurements taken at least 4 months apart during treatment.

The researchers estimated exposure to metformin and other diabetes medications through pharmacy claims that showed fill frequency and dose. Relations between metformin exposure and HbA1c were quantified through regression analysis and stratified by race and ethnicity.

From baseline HbA1c values of 7.81% (61.8 mmol/mol) in blacks and 7.38% (57.1 mmol/mol) in whites, metformin was associated with an overall 0.62% (6.8 mmol/mol) HbA1c reduction with a significant difference by race and ethnicity compared with no use.

Metformin use was associated with a 0.9% (9.8 mmol/mol) HbA1c reduction in blacks and a 0.42% (4.6 mmol/mol) HbA1c reduction in whites (P<.001). Treatment was associated with lower HbA1c levels in blacks, regardless of baseline values.

“Further studies are needed to assess whether the greater reduction in HbA1c levels in African Americans also translates to greater improvement in hard clinical outcomes, such as microvascular events, including retinopathy and nephropathy, and macrovascular, including myocardial infarction and peripheral vascular disease,” Williams said. — by Allegra Tiver

For more information:
Williams can be reached at the Henry Ford Health System, 1 Ford Place, 3A, Detroit, MI 48202; email:

Disclosure: This research was supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Allergy and Infectious Diseases, the National Heart, Lung, and Blood Institute, NIH and the Fund for Henry Ford Hospital.