The DREAM study, Are we preventing or just delaying diabetes?

The results of the DREAM study have published in the NEJM (ramipril arm) and the Lancet ( rosiglitizone arm) . This trial will get a lot of press and in the eyes of cynical old docs like me a lot of spin. Fortunately, the eagle eyed and clear thinking world of medical bloging will have offer anti-spin or at the least an opinion a bit different from the pharm company's press releases ( see here and here ) and the repetition of some of it by main stream media .

DREAM was large randomized clinical trial involving patients with the label pre-diabetes ( impaired fasting glusoce and/or glucose intolerance) and the aim was to see if a TZD (thiazolidenedione) and/or an ace inhibitor would prevent the progression of pre diabetes to diabetes. The rosi group received daily rosiglitizone for 3 years plus education regarding diet and exercise and 11.6 % progressed to diabetes in 3 years versus 26% of the placebo group.In the rosi group 0.5% developed heart failure versus 0.1% in the placebo group.The ramipril trial was negative in the sense of no effect on the development of diabetes.

Here is how the study's authors framed things in the final paragraph of their discussion section-paraphrased- If you treat 1000 patients for three years with rosiglitizone, 144 cases of diabetes will be prevented and 5 will develop heart failure.

The problem I have with that is the use of the word "prevented". I take prevent to mean you will not develop a condition. In this situation I believe you are simply delaying what seems to be almost always the case in type 2 diabetes-and by extension pre-diabetes- progressive worsening of the glucose control. Here prevention seems to mean to "prevent" diabetes for three years. The data is just not sufficient to make the statement that diabetes has been prevented.To be able to say that you would need a really long follow up.

It is well known that TZDs can improve blood sugar control in diabetes and it is no surprise it could do the same in patients with early diabetes -or pre-diabetes-and it is also well known that they may cause fluid retention and heart failure. so I see nothing really new here except what I think is exaggerated talk about prevention.

The comments made after the Diabetes Prevention Trial( o.k., they called it prevention)were much more appropriately circumspect. That trial compared exercise plus diet, metformin and a control group all with glucose intolerance and over a 3 year period 29% of the control group , 22% of the metformin group and 14% of the exercise/diet group developed diabetes."We simply don't know how long beyond the 3 year period diabetes can be delayed " was the comment made by one of the study's authors. This is a study whose results I frequently discussed with overweight patient with borderline blood sugars in the hope of encouraging life style changes but I did not promise diabetes would be prevented.