There is no such thing as “the five most terrible complications of diabetes”, but the common serious complications of diabetes are diabetic foot, diabetic nephropathy, hyperosmolar hyperglycemia syndrome, etc. The most common complications of diabetes are diabetic foot, diabetic nephropathy, hyperosmolar hyperglycemia syndrome and so on. 1. Diabetic foot: the most important cause of diabetic non-traumatic amputation. In mild cases, it is characterized by foot deformity, dry and cold skin, etc. In severe cases, foot ulceration and gangrene may occur. 2. Diabetic nephropathy: it is the main cause of end-stage renal failure, which can be manifested as proteinuria, edema, hypertension and other symptoms. 3. Hyperosmolar hyperglycemia syndrome: it is one kind of acute metabolic disorder of diabetes mellitus, characterized by severe hyperglycemia, high plasma osmolality and dehydration, and patients may have different degrees of consciousness disorder or coma. In addition to the above complications, other common serious clinical complications include diabetic retinopathy and diabetic peripheral neuropathy. If you are diagnosed with diabetes or experience any of the above symptoms, please go to the hospital in time to avoid delaying your condition!