Metformin, Diet/Exercise Comparable at Cutting Diabetes Risk in Women With GDM

Neil Osterweil

June 07, 2004

June 7, 2004 (Orlando) — Newly released data from the Diabetes Prevention Program (DPP) suggest that either metformin or intensive lifestyle interventions are highly effective in preventing the onset of type 2 diabetes mellitus (DM) in women with a history of gestational diabetes mellitus (GDM). The research was presented here at the 68th annual meeting of the American Diabetes Association.

But in women who had children but no history of GDM, lifestyle interventions were significantly more effective than metformin at preventing or delaying type 2 DM, said Robert E. Ratner, MD, from the MedStar Research Institute in Hyattsville, Maryland.

"The remarkable aspect is that metformin is far more effective in women with a history of GDM than it was in women without a history. [Metformin] was far more effective, equivalent to lifestyle interventions," said Dr. Ratner in an interview with Medscape.

Of a total of 2,191 women enrolled in the study, 349 had a self-reported history of GDM, 1,416 had given birth at least once but had no self-reported history of GDM, and 426 women had not given birth to live children. The women were randomly assigned to receive either instruction in intensive lifestyle changes or to metformin or placebo. Patients and investigators were blinded to the treatment regimen. Baseline metabolic parameters were similar between the two groups, as were other baseline characteristics with the exception of age at study entry: women with a history of GDM had a mean age of 43 years, compared with a mean age of 54 years for women with no GDM history.

The researchers found that in women who reported a history of GDM, either metformin or lifestyle changes reduced the relative risk of later type 2 DM by about 54%. In contrast, the relative risk reduction associated with metformin was 14% in women with no history of GDM compared with 51% for lifestyle changes.

A previously reported analysis of DPP trial data, published in the Feb. 7, 2002, issue of the New England Journal of Medicine, showed that, overall, metformin reduced the risk of DM by about 31% compared with a 58% reduction for those assigned to intensive nutrition and exercise counseling.

In the current study, the risk reduction occurred in the women with prior GDM despite the fact they lost less weight and tended to regain weight sooner and to a higher degree than the women without a history of GDM.

"We know [GDM] is a huge risk for the development of diabetes. What this is telling us is that GDM is probably a much bigger risk for developing diabetes than we previously thought," said Martin Abrahamson, MD, chief medical officer at the Joslin Diabetes Center in Boston, Massachusetts, in an interview with Medscape. Dr. Abrahamson was not involved in the study.

Dr. Ratner told Medscape that "when you begin to look at the natural history, if a woman has had a history of gestational diabetes, even after 10 years postpartum, her risk of developing diabetes itself is 70% higher than a comparable group of women without GDM.... Something about GDM is identifying a much, much higher risk patient population."

Data from the DPP suggest that patients with GDM need to be followed for much longer than previously thought, Dr. Ratner said. "The risk persists, as far as we can tell, forever."

"What I would say is that we need to be very aggressive with these patients," Dr. Abrahamson told Medscape. "I've always said that lifestyle modification is the way to go, but that being said, is it time for us to start thinking about the prevention of the disease with pharmacotherapy, knowing that pharmacotherapy is as effective as it is."

ADA 64th Annual Scientific Sessions: Concurrent session. Presented June 5, 2004.

Reviewed by Gary D. Vogin, MD


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