Diabetes mellitus ( or , or ), often referred to simply as diabetes (Ancient Greek: "to pass through urine"), is a syndrome of disordered metabolism, usually due to a combination of hereditary and environmental causes, resulting in abnormally high blood sugar levels (hyperglycemia). Blood glucose levels are controlled by the hormone insulin made in the beta cells of the pancreas.

Diabetes develops due to a diminished production of insulin (in type 1) and resistance to its effects (in type 2 and gestational). Both lead to hyperglycemia, which largely causes the acute signs of diabetes: excessive urine production, resulting compensatory thirst and increased fluid intake, blurred vision, unexplained weight loss, lethargy, and changes in energy metabolism. Monogenic forms, e.g. MODY, constitute 1-5 % of all cases.

All forms of diabetes have been treatable since insulin became medically available in 1921, but there is no cure. The injections by a syringe or insulin pump deliver insulin, which is a basic treatment of type 1 diabetes. Type 2 is managed with a combination of dietary treatment, tablets and insulin supplementation. Different types of MODY share the treatment with type 1 or type 2.

Diabetes and its treatments can cause many complications. Acute complications (hypoglycemia, ketoacidosis, or nonketotic hyperosmolar coma) may occur if the disease is not adequately controlled. Serious long-term complications (i.e., chronic side effects) include cardiovascular disease (doubled risk), chronic renal failure, retinal damage (which can lead to blindness), nerve damage (of several kinds), and microvascular damage, which may cause impotence and poor wound healing. Poor healing of wounds, particularly of the feet, can lead to gangrene, and possibly to amputation. Adequate treatment of diabetes, as well as increased emphasis on blood pressure control and lifestyle factors (such as not smoking and maintaining a healthy body weight), may improve the risk profile of most of the chronic complications. In the developed world, diabetes is the most significant cause of adult blindness in the non-elderly and the leading cause of non-traumatic amputation in adults, and diabetic nephropathy is the main illness requiring renal dialysis in the United States.

A Certified diabetes educator (CDE) is a health care professional who is specialized and certified to teach people with diabetes how to manage their condition The American Diabetes Association

Center for Diabetes Care.

The CDE is an invaluable asset to those who need to learn the tools and skills necessary to control their blood sugar and avoid long-term complications due to hyperglycemia. Unlike an endocrinologist, the CDE can spend as much time with a newly diagnosed person as is needed both for educational purposes and emotional support.

Typically the CDE is also a nurse, dietitian, pharmacist or social worker who has further specialized in diabetes education and care management. Formal education and years of practical experience are required, in addition to a formal examination, before a diabetes educator is certified. In the US, certification is awarded by the National Certification Board for Diabetes EducatorsAmerican Association of Diabetes EducatorsNational Certification Board for Diabetes Educators

. In Canada, certification is awarded by the Canadian Diabetes Educator Certification Board. (CDECB)

In the Philippines, any allied health care professional may apply to be a diabetes educator after taking special courses from the Philippine Association of Diabetes Educators (PADE) or Association of Diabetes Nurse Educators of the Philippines (ADNEP)Philippine Association of Diabetes Educators. Qualified graduates of diabetes educator courses can practice as a professional diabetes educator in any Center for Diabetes Care (CDC) clinic network. The Diabetes Nurse Educator (DNE) and Certified Lay Educator (CLE) are the equivalent of CDE certificate in the Philippines.