Pre-diabetes means blood glucose levels are higher than normal but not high enough to be diagnosed with diabetes.
Pre-diabetes raises the risk of developing type 2 diabetes and cardiovascular disease, including heart disease and stroke
Reference
National Institute of Diabetes and Digestive and Kidney Diseases. National Diabetes Statistics fact sheet: General information and national estimates on diabetes in the United States, 2007. Bethesda, MD: U.S. Department of Health and Human Services, National Institutes of Health, 2008.