Lowering the Cut Point for Impaired Fasting Glucose
Where is the evidence? Where is the logic?
- David L. Schriger, MD, MPH12 and
- Brett Lorber, MD, MPH1
- 1Emergency Medicine Center, University of California Los Angeles School of Medicine, Los Angeles, California
- 2Centre for Statistics in Medicine, Institute of Health Sciences, Oxford, England
- Address correspondence and reprint requests to David L. Schriger, UCLA Emergency Medicine Center, 924 Westwood Blvd., Suite 300, Los Angeles, CA 90021-2924. E-mail: schriger{at}ucla.edu
First a disclaimer, neither of us is a diabetologist, endocrinologist, or internist. We do not provide chronic care to people with diabetes. Our only credential relevant to the diagnosis of diabetes is our willingness to think logically and our conviction that the goal of guidelines and policies must be to optimize patient outcomes. From this perspective we are befuddled by the Expert Committee’s (1) decision to lower the cut point for impaired fasting glucose (IFG) from 110 to 100 mg/dl. In this commentary we explain why.
With the publication of the Expert Committee’s report (1) in Diabetes Care in November 2003, the number of 25- to 74-year-olds in the U.S. with IFG instantly tripled from 10 to 35 million people (see appendix for all methods). We might expect that a decision affecting over 25 million people would be based on some type of explicit modeling that established the benefits of the new cut point. Unfortunately, the Expert Committee’s report contains no such analysis. In fact, the committee states “we do not yet know the total benefit or the total cost to an individual who is designated at risk for diabetes by either test, by any criteria” (1). Given this, the Expert Committee might have concluded, “and we therefore have insufficient evidence to newly label 25 million people with IFG” (1).
Instead, the committee offers two forms of justification for its decision: 1) epidemiological data that suggest that those with an FPG of 100–109 mg/dl may be at higher risk for developing diabetes than those with a level below 100 mg/dl; and 2) the desire to have the IFG population have greater homology to the impaired glucose tolerance (IGT) population. The first argument fails because identifying those at higher risk in no way insures that their health will be improved …
