Consultations & Comments: How to Prevent Diabetes?

In their article, "Diabetes: How Early--and Aggressively--to Intervene?" (CONSULTANT, November 2005, page 1416), Drs Thomas Clark and John R. Holman discussed the results of the lifestyle intervention and metformin arms of the Diabetes Prevention Program (DPP) study. However, the authors neglected to include data from the troglitazone arm of the DPP study.

I am concerned that the potential benefits of thiazolidinediones (TZDs) have been significantly underutilized in efforts to prevent diabetes. In part, this is a result of the late and disconnected publication of data from the DPP's troglitazone arm.¹ The message from the DPP study as a whole--that intensive lifestyle interventions are superior to drug therapy--is loud and clear. However, diabetes is still developing in my adult patients despite our best efforts at lifestyle intervention. If troglitazone reduced the incidence of diabetes onset by 75% in the DPP--compared with a 58% reduction with lifestyle interventions alone or a 44% reduction with metformin--shouldn't we be considering TZDs earlier in the course of diabetes, in conjunction with intensive lifestyle interventions?

---- Steven Tatar, MD

Charlottesville, Va

Although I have used TZDs to prevent diabetes in certain patients, there are no data on current FDA-approved agents in this class to support the practice. Two studies of troglitazone (the Troglitazone In Prevention Of Diabetes [TRIPOD] trial and unpublished data from the DPP) show about a two-thirds reduction in the progression to diabetes; however, no studies of pioglitazone or rosiglitazone for prevention have been conducted. Also, the very striking numbers in the DPP were seen over a period only half as long as that used for the rest of the study; the troglitazone arm was stopped because of one death from liver failure and liver toxicity in other patients. I hope that TZDs will one day be shown to be the most effective preventive treatment, but until the evidence is available, exercise is by far the best strategy for preventing diabetes.

---- Thomas Clark, MD

United States Navy

References:

REFERENCE:

1.

Knowler WC, Hamman RF, Edelstein SL, et al; Diabetes Prevention Program Research Group. Preventionof type 2 diabetes with troglitazone in the Diabetes Prevention Program. Diabetes. 2005;54:1150-1156.