"Remarkable" Effect of Metformin

Metformin played an important role in reducing the risk of type 2 diabetes developing in women with gestational diabetes (GDM), according to new research.

During the landmark Diabetes Prevention Program (DPP), GDM increased the risk of progression to diabetes in 3,234 women, but intensive lifestyle intervention (ILS) and metformin therapy reduced overall risk of diabetes onset by 58% and 31%, respectively, compared with placebo. In women with a history of GDM, intensive lifestyle intervention and metformin reduced incidence of diabetes progression by approximately half.

The authors of the current study followed up with 288 women with a history of GDM and 1,226 women with no self-reported history of GDM who participated in the DPP to see if the positive effects of healthier lifestyle choices and metformin therapy were sustained for 7 years beyond the study’s original 3-year assessment.

Two-thirds of women with GDM were likely to progress to diabetes compared with half of women without history of the condition, according to the current study, which noted risk of diabetes increased by nearly half in women with GDM.

In results similar to the 3-year follow-up, intensive lifestyle intervention and metformin reduced the risk of diabetes by 35% and 40%, respectively. The researchers said diabetes would be prevented over 10 years in 1 out of every 8 women treated with metformin and 1 out of every 12 women who made healthy lifestyle changes.

Metformin reduced incidence of diabetes in women with GDM by 40% compared with placebo, said the researchers, who noted that the drug reduced the overall risk of diabetes at 10 years by 18%, a finding that showed the therapy is particularly effective in high-risk women. In agreement with the initial 3-year follow-up, metformin did not have significant impact in limiting the progression to diabetes in women without GDM.

Although the study’s design may have excluded women at the highest risk of progressing to diabetes and included some women in the non-GDM group with undiagnosed diabetes, the researchers observed “substantial” risk of diabetes over the follow-up period and “remarkable effects” of the interventions.

The researchers said women with high body-mass indexes, elevated fasting glucose levels, impaired glucose tolerance, and history of GDM are at increased risk of developing diabetes at 3 and 10 years.

“Our follow-up study found the elevated risk of developing type 2 diabetes persisted for years in women who had been diagnosed with gestational diabetes, and this long-term risk can be reduced with either intensive lifestyle intervention or the medication metformin,” said study co-author author Dr. Vanita Aroda, of the MedStar Health Research Institute in Hyattsville, Maryland.

“Medical and lifestyle interventions were remarkably effective at slowing the progression of type 2 diabetes in this at-risk population in both the short and long term,” she added.

The study was published online in the Journal of Clinical Endocrinology and Metabolism.

—Dan Cook

Reference:

1. Aroda VR, Christophi CA, Edestein SL, et al. The effect of lifestyle intervention and metformin on preventing or delaying diabetes among women with and without gestational diabetes: the diabetes prevention program outcomes study 10-year follow-up. J Clin Endocrinol Metab. 2015 Feb 23. [Epub ahead of print]