Patient history drives metformin efficacy in IGT: lifestyle changes and metformin were equally effective in women with a history of GDM.(CLINICAL ROUNDS)

Both intensive lifestyle changes and metformin can significantly reduce the risk of diabetes in women with impaired glucose tolerance who have had gestational diabetes mellitus, a subanalysis of the Diabetes Prevention Program has concluded.

Both interventions reduced the risk of diabetes progression by about 50% compared with placebo, Dr. Robert Ratner and his colleagues reported in the Journal of Clinical Endocrinology and Metabolism.

However, in women without a history of gestational diabetes mellitus (GDM), lifestyle changes were significantly more effective than was metformin in preventing diabetes (49% vs. 14%), the investigators wrote (J. Clin. Endocrinol. Metab. 2008;93:4774-9).

"Our data suggest a differential success of the interventions between those with and without a history of gestational diabetes," wrote Dr. Ratner of the MedStar Research Institute, Hyattsville, Md.

Lifestyle changes were probably not as effective in those women who had experienced GDM because that group had a much harder time losing weight and keeping it off than did those who had never had the disorder, thus equalizing the effect of both treatments, the investigators wrote.

The Diabetes Prevention Program study examined the risk of progression to diabetes in women with impaired glucose tolerance.

The study randomized patients to placebo, metformin, or intensive lifestyle changes, which included increasing physical activity at least 1.5 hours per week over baseline for the duration of the 3-year trial.