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The aim of our study was to find out how common diabetes and, more interestingly, other glucose and insulin abnormalities (e.g. pre-diabetes) are in patients with different types of cardiovascular disease (CVD - disease of the heart or arteries) or risk factors for CVD.
NAVIGATOR (Nateglinide and Valsartan in IGT Outcomes Research trial) is a massive global effort involving about 790 investigators in 40 countries.
NAVIGATOR investigators screened over 39,000 subjects with CVD/risk factors for CVD, not known to be diabetic, with a single oral glucose tolerance test (a test which examines how the body copes with a sugar load). NAVIGATOR is the first study to use this test in such a global way.
49% of people screened were men and their average age was 63 years. We found that approximately 1 in 5 subjects screened had previously undiagnosed diabetes. More than 1 in 4 additional subjects had impaired glucose tolerance, a pre-diabetic condition which frequently progresses to full-blown diabetes over time. Only about a third of subjects had normal glucose and insulin metabolism.
Why are these findings surprising and important in this group of people? Firstly, the finding that diabetes is already present in a significant number of people, but undiagnosed, is of concern. This is because we know that if diabetes is detected and rigorously controlled complications such as eye problems, nerve damage and kidney failure can be reduced. Secondly, the similarly high rate of impaired glucose tolerance is also alarming. We know that the development of full-blown diabetes is associated not only with eye, kidney and nerve problems but also with much worse outcomes from heart and blood vessel problems, including a higher risk of death. Prevention of the progression of impaired glucose tolerance to full-blown diabetes may, therefore, be very important in reducing these individuals' risk of cardiovascular and other medical problems. Previous studies have shown that changes in diet and exercise can reduce the risk of developing diabetes in subjects with impaired glucose tolerance. NAVIGATOR is a randomised trial investigating whether two treatments, nateglinide and valsartan, individually or in combination, can further reduce the risk of diabetes in these subjects and also prevent cardiovascular problems such as heart attacks and stroke.
In summary, physicians need to recognise that undiagnosed diabetes is common in patients with cardiovascular disease (and at risk of cardiovascular disease) and that failure to recognise this denies these patients appropriate treatment and the best chance of avoiding future diabetic complications. Similarly, the pre-diabetic condition of impaired glucose tolerance is equally common in these individuals. Lifestyle change can reduce the risk of developing full-blown diabetes, with all the sinister implications of that development. More research is needed to find additional ways of reducing this risk and NAVIGATOR is currently the largest and most advanced clinical trial in this area.
JJ McMurray (Glasgow, GB)
This press release accompanies both a presentation and an ESC press conference given at the ESC Congress 2004. Written by the investigator himself/herself, this press release does not necessarily reflect the opinion of the European Society of Cardiology