Diabetes is a common chronic medical condition that leads to increased blood sugar (glucose) levels. Severe complications can come from diabetes, including heart disease, vascular (blood vessel) disease and poor circulation, blindness, kidney failure, poor healing, stroke, and other neurological (nerve) diseases. Diabetes cannot be cured but can be successfully treated. Complications from diabetes can be prevented with careful blood sugar management and control of high blood pressure and high cholesterol levels when present. The April 15, 2009, issue of JAMA is a theme issue devoted to articles about diabetes.