Monday, June 20, 2005
Latest Mild cognitive Impairment treatment trial:disappointing results
The June 9, 2005 issue of NEJM published results of a treatment trial of mild cognitive impairment(MCI)with Vitamin E and donepezil which was disappointing in several regards.Vitamin E, which had previously been shown to be of slight benefit(by the same research group which published the NEJM paper) in moderate to severe ALzheimer's Disease seemed without benefit in this group of patients with the amnestic type of MIC many of whom probably have "very mild" Alzheimer's Disease.Although donepezil did not change the rate of progression to Alzheimer's in three years (this was the primary end point of the study)it did seem to decrease the rate of progression in the first twelve months of treatment. The treatment effect was slight and transient in the group as a whole. A subgroup(those who were carriers for APOEe4) did show a slowed progression for the entire 36 months.The bad news continued in the related editorial which informs us that preliminary results from 2 other trials with galantamine also have negative results over a two year period.So even though we seem to be able to detect very early dementia with functional brain imaging,there is no treatment available of proven efficacy.Now a question for the two medical students who sometimes read this blog.When two RCTS are done by the same group and one shows that Vit E helps moderate to severe Alheimer's disease and one shows no effect in MCI which appears at least most of the time to be really very mild Alzheimer's, which do you believe ? Or for that matter,let us address the question to the masters of EBM.