Kidney Function

A 64-year-old man with a 15-year history of poorly controlled type 2 diabetes and a 10-year history of hypertension and hyperlipidemia had developed multiple diabetes-related complications within the last 5 years. He first developed albuminuria 5 years ago, and during the next several years, he experienced a fairly rapid decrease in kidney function, with an estimated glomerular filtration rate of 55 mL/min/1.73 m2 noted 2 years ago. Proliferative retinopathy was diagnosed 5 years ago, and he underwent laser photocoagulation. Four years ago, he noted symptoms of peripheral neuropathy manifested as shooting pain and numbness with loss of light touch, thermal, and vibratory sensation in a stocking distribution. Last year, he developed a nonhealing ulcer on the plantar aspect of his left foot that was complicated by gangrene and resulted in a below-the-knee amputation of the left leg 1 year ago. He now reports new onset of weakness, lightheadedness, and dizziness on standing that affects his daily activities. He reports lancinating pain in his right lower extremity, worse in the evening. Medications include neutral protamine Hagedorn insulin twice daily and regular insulin on a sliding scale; metoprolol, 50 mg/d; lisinopril, 40 mg/d; atorvastatin, 80 mg/d; furosemide, 40 mg/d; and aspirin, 81 mg/d. Blood pressure is 127/69 mm Hg with a pulse rate of 96 beats/min while supine and 94/50 mm Hg with a pulse rate of 102 beats/min while standing. Strength is normal, but with complete loss of all sensory modalities to the knee in his remaining limb and up to the wrists in both upper extremities, and he is areflexic. Today’s laboratory evaluations show a serum creatinine level of 2.8 mg/dL, estimated glomerular filtration rate of 24 mL/min/1.73 m2, hemoglobin A1c level of 7.9%, and urine protein excretion of 2.1 g/1 g of creatinine. What would be the most appropriate management for this patient?