High Risk of Cardiovascular Mortality in Individuals With Impaired Fasting Glucose Is Explained by Conversion to Diabetes
The Hoorn Study
- Josina M. Rijkelijkhuizen, PHD1,
- Giel Nijpels, MD, PHD12,
- Robert J. Heine, MD, PHD13,
- Lex M. Bouter, PHD1,
- Coen D.A. Stehouwer, MD, PHD14 and
- Jacqueline M. Dekker, PHD1
- 1EMGO Institute, VU University Medical Center, Amsterdam, the Netherlands
- 2Department of General Practice, VU University Medical Center, Amsterdam, the Netherlands
- 3Department of Endocrinology, VU University Medical Center, Amsterdam, the Netherlands
- 4Department of Internal Medicine, Academic Hospital Maastricht, Maastricht, the Netherlands
- Address correspondence and reprint requests to Josina M. Rijkelijkhuizen, EMGO Institute, VU University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, Netherlands. E-mail: j.rijkelijkhuizen{at}vumc.nl
Abstract
OBJECTIVE—To optimize identification of future diabetic patients, the American Diabetes Association (ADA) introduced criteria for impaired fasting glucose (IFG) in 1997 (IFG 6.1 mmol/l [IFG6.1]) and lowered the threshold from 6.1 to 5.6 mmol/l (IFG5.6) in 2003. Our aim was to assess the consequences of lowering the IFG cutoff on the risk of cardiovascular disease (CVD) mortality and to evaluate whether this risk is explained by a conversion to type 2 diabetes within 6.4 years.
RESEARCH DESIGN AND METHODS—In a population-based cohort, the Hoorn Study, plasma glucose was determined in 1989 and 1996 (n = 1,428). Subjects were classified in 1989 according to 1997 and 2003 ADA criteria. Subjects with IFG in 1989 were further classified according to diabetes status in 1996. Hazard ratios for CVD mortality (n = 81) in the period 1996–2005 were adjusted for age and sex.
RESULTS—Subjects with IFG6.1, but not IFG5.6, had a significantly higher CVD mortality risk than normal fasting glucose (NFG) subjects. Subjects who converted from IFG to diabetes (IFG6.1: 42%; IFG5.6: 21%) had a more than twofold risk of CVD mortality (IFG6.1: 2.47 [1.17–5.19]; IFG5.6: 2.14 [1.12–4.10]) than subjects with NFG. IFG subjects who did not develop diabetes did not have significantly higher CVD mortality risks (IFG6.1: 1.50 [0.72–3.15]; IFG5.6: 1.15 [0.69–1.93]).
CONCLUSIONS—The lower cutoff for IFG (ADA 2003 criteria) results in a category of IFG that no longer represents a high-risk state of CVD. Furthermore, only subjects who convert from IFG to diabetes have a high risk of CVD mortality.
- ADA, American Diabetes Association
- CVD, cardiovascular disease
- FPG, fasting plasma glucose
- IFG, impaired fasting glucose
- IFG5.6, IFG cutoff of 5.6 mmol/l
- IFG6.1, IFG cutoff of 6.1 mmol/l
- OGTT, oral glucose tolerance test
Footnotes
-
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C Section 1734 solely to indicate this fact.
-
- Accepted October 22, 2006.
- Received June 15, 2006.
- DIABETES CARE
