A 60-year-old man comes to the office due to edema of his face and ankles for the last 2 weeks. He has had no chest pain or breathlessness. The patient has a 15-year history of type 2 diabetes mellitus, which is currently managed with exercise, dietary modification, and glipizide. A month ago, his glycosylated hemoglobin level was 6.9%. Temperature is 37 C (98.6 F), blood pressure is 146/87 mm Hg, pulse is 75/min, and respirations are 15/min. Physical examination shows periorbital edema and bilateral pitting edema around the ankles. The remainder of the examination is normal. Laboratory studies are as follows: The patient's electrocardiogram is normal. Urine protein is 3,700 mg/24 hr. Which of the following measures is most likely to slow the progression of this patient's kidney disease?

Question

A 60-year-old man comes to the office due to edema of his face and ankles for the last 2 weeks.  He has had no chest pain or breathlessness.  The patient has a 15-year history of type 2 diabetes mellitus, which is currently managed with exercise, dietary modification, and glipizide.  A month ago, his glycosylated hemoglobin level was 6.9%.  Temperature is 37 C (98.6 F), blood pressure is 146/87 mm Hg, pulse is 75/min, and respirations are 15/min.  Physical examination shows periorbital edema and bilateral pitting edema around the ankles.  The remainder of the examination is normal.  Laboratory studies are as follows:  The patient's electrocardiogram is normal.  Urine protein is 3,700 mg/24 hr.  Which of the following measures is most likely to slow the progression of this patient's kidney disease?

Quizplus · Accepted Answer

This patient has long-standing type 2 diabetes mellitus complicated by significant diabetic nephropathy (DN). Initially, DN is characterized by hyperfiltration (ie, increased glomerular filtration rate [GFR]); however, as the disease progresses, GFR falls, manifesting as a rising serum creatinine level. Concurrently, glomerular protein losses lead to moderately increased albuminuria (urine protein excretion 30-300 mg/day; previously termed microalbuminuria) and eventually severely increased albuminuria (>300 mg/day). As in this patient, advanced DN can present with frank proteinuria and nephrotic syndrome. hyperfiltration In patients with type 2 diabetes, intensive blood pressure control is associated with reduced progression of DN; the ideal blood pressure (BP) is uncertain, although a target of <130/80 mm Hg is reasonable and achievable for most patients. ACE inhibitors and angiotensin II receptor blockers are the preferred antihypertensive drugs; these agents lower systemic BP and also reduce intraglomerular pressure, which may be renoprotective. (Choices A and B) Intensive lipid control with statins can reduce the risk for coronary heart disease; however, lipid-lowering therapy has not clearly been shown to reduce the progression of nephropathy. Low-dose aspirin also may reduce the incidence of cardiovascular events but would not slow the progression of nephropathy. (Choice D) Intensive glycemic management to a target hemoglobin A1c <7% can slow the progression of DN; however, this patient has good overall glycemic control (A1c of 6.9%), and futher lowering is associated with an increased risk for hypoglycemia and may actually increase the risk for cardiac events. Although sodium-glucose cotransporter 2 inhibitors also reduce the risk of kidney disease progression in patients with type 2 diabetes with nephropathy, these drugs can only be used in patients with an estimated GFR of ≥30 mL/min/1.73 m² and are limited in use due to cost and adverse effects (eg, urinary tract infections). ² (Choice E) A moderate restriction in protein intake (eg, <1 g/kg/day) in patients with type 2 diabetes may slow the progression of DN, but the benefits are small. Very low protein intake is not advised because patients with diabetes often have some degree of protein wasting at baseline and additional, complex dietary requirements. Educational objective: Strict blood pressure control, particularly using ACE inhibitors or angiotensin II receptor blockers, can reduce the progression of diabetic nephropathy (DN). Tight glycemic control with a target hemoglobin A1c <7% also can prevent progression of DN; further lowering is associated with an increased risk of hypoglycemia and possibly cardiac events. References: Blood pressure, hypertension, RAAS blockade, and drug therapy in diabetic kidney disease. (http://www.ncbi.nlm.nih.gov/pubmed/24780456)

A 60-Year-Old Man Comes to the Office Due to Edema