Metformin can prevent postpartum diabetes

NEW YORK (Reuters Health) - Following gestational diabetes, a type of diabetes that developments during pregnancy and usually goes away after pregnancy, treatment with metformin or intensive lifestyle interventions can prevent or delay diabetes from becoming permanent in the postpartum period, new research shows.

Lead author Dr. Robert E. Ratner at Medstar Research Institute in Hyattsville, Maryland, and co-researchers evaluated responses to each intervention among pregnant women with impaired glucose tolerance, a major risk factor fore diabetes, enrolled in the prospective Diabetes Prevention Program.

The current subgroup analysis, reported in the Journal of Clinical Endocrinology and Metabolism, included 350 women with a history of gestational diabetes and 1416 with no such history. Subjects were randomly assigned in a 1:1:1 ratio to metformin therapy, intensive lifestyle intervention - exercise and diet), or placebo.

Although all women entered the trial with similar glucose levels, those with a history of gestational diabetes in the placebo group had a 71-percent increased incidence of diabetes compared with control subjects during 3 years of follow-up.

However, metformin was associated with a 50-percent reduction and the intensive lifestyle modification with a 53-percent reduction in the risk of developing diabetes following gestational diabetes, Ratner and associates report.

Among women without a history of gestational diabetes, lifestyle modification reduced the risk by 49 percent, while metformin reduced the risk by only 14 percent, which was not statistically significant.

The authors estimate that five to six women with gestational diabetes and impaired glucose tolerance would need to be treated over 3 years with either metformin or lifestyle modification to prevent one case of diabetes.

The corresponding numbers needed to treat the control subjects with impaired glucose tolerance were 9 for intensive lifestyle intervention and 24 for metformin.

"Continued follow-up and testing for diabetes should be part of the lifetime assessment of women with a history of gestational diabetes mellitus," Ratner's team adds.

"We need to commit ourselves to caring for women with gestational diabetes mellitus when they are not pregnant," Dr. Jeffrey L. Ecker, at Harvard Medical School in Boston, writes in an accompanying editorial.

Ecker recommends that these women be told of the importance of regular follow-up, and that healthcare providers be aware of the risks of these patients.

SOURCE: Journal of Clinical Endocrinology and Metabolism, December 2008.