(HealthDay News) — Race-ethnicity appears to influence the effect of metformin on glycemic control in patients with diabetes, according to research published online June 12 in the Journal of Clinical Endocrinology & Metabolism.

L. Keoki Williams, MD, MPH, of the Henry Ford Health System in Detroit, and colleagues examined the effects of metformin on glycated hemoglobin (HbA1c) measurements in 19,672 patients with diabetes, including 7,429 African Americans and 8,783 European Americans.

The researchers found that baseline HbA1c levels among patients with diabetes were higher in African Americans (7.81%; 61.8mmol/mol) than in European Americans (7.38%; 57.1mmol/mol). Metformin therapy, compared with no use, was associated with a 0.62% (6.8mmol/mol) reduction in HbA1c level. Reduction in HbA1c levels was significantly greater in African Americans than in European Americans (0.90% or 9.8mmol/mol vs. 0.42% or 4.6mmol/mol; P<0.001). Regardless of baseline HbA1c level, use of metformin was associated with lower HbA1c levels in African-American patients.

“African-American individuals appear to have a better glycemic response to metformin when compared with European Americans,” the authors write. “Further studies are needed to determine whether this translates to commensurate reductions in diabetes complications.”

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