A 54-year-old patient has been suffering from diabetes mellitus for 5 years, with diet being his only treatment. Within the last half a year he lost 7 kg of body weight, complains of thirst, vertigo when raising from bed, decrease of erectile function, frequent stool, especially at night. Objectively: malnutrition, dry skin. BP in lying position is 160/90 mm Hg; BP in standing position is 170/85 mm Hg. No edemas. Fasting plasma glucose level is 12 mmol/l. Glycated hemoglobin accounts for 11%. Albumin excreted with urine is 20 mg per day. The most likely diagnosis is: