Diabetes treatment. Diabetic patient having his feet washed by a nurse on a home visit. Diabetes is a condition caused by lack of the hormone insulin, which leads to uncontrolled carbohydrate metabolism. A complication of diabetes is disruption of blood flow to the limbs or neuropathy (nerve damage) caused by the disease. Ulcers and gangrene can result. Careful washing and dressing of the affected area can help, however, amputation may often be necessary.