Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.
A 60-year-old man is evaluated as a new patient. He was diagnosed with type 2 diabetes mellitus during a health insurance evaluation 6 months ago. At that time, metformin was initiated. Medical history is otherwise unremarkable.
On physical examination, blood pressure is 145/94 mm Hg; other vital signs are normal. BMI is 29. The remainder of the examination is unremarkable.
Laboratory studies show an HbA1c of 6.8%, blood urea nitrogen 10 mg/dL (3.6 mmol/L), serum creatinine 0.9 mg/dL (79.6 µmol/L), glucose 126 mg/dL (7 mmol/L), urinalysis normal, and urine albumin–creatinine ratio 20 mg/g.
Electrocardiogram reveals left ventricular hypertrophy.
Which of the following is the most appropriate next step in management?
A. Add an ACE inhibitor
B. Add a beta-blocker
C. Add a calcium channel blocker
D. Add a diuretic
E. Continue current regimen
MKSAP Answer and Critique
The correct answer is A. Add an ACE inhibitor.
An ACE inhibitor is indicated for this patient with type 2 diabetes mellitus who has hypertension and normal urine albumin excretion. Because of the increased risk of cardiovascular and kidney disease associated with diabetes, control of hypertension is essential in the management of patients with diabetes. Although the benefit of treatment of hypertension with ACE inhibitors has been well established in diabetic patients with albuminuria by preventing progression of proteinuria and subsequent decline in glomerular filtration rate, there is also evidence that interruption of the renin-angiotensin system may decrease the risk of developing microalbuminuria in hypertensive, type 2 diabetic patients. This effect of treating hypertension with an ACE inhibitor (or angiotensin receptor blocker [ARB]) in these patients with normal urine albumin excretion appears to be independent of the achieved blood pressure compared with similar hypertension control with other antihypertensive agents. In diabetes, glomerular hyperfiltration mediated by the renin-angiotensin-aldosterone system is very important in the pathogenesis and progression of diabetic nephropathy. The use of ACE inhibitors or ARBs reduces the glomerular hyperfiltration. This patient’s blood pressure is greater than 140/90 mm Hg, and he is unlikely to reach his goal with lifestyle modifications alone. Therefore, he requires pharmacologic treatment, preferentially with an ACE inhibitor or ARB, for his hypertension until he reaches the American Diabetes Association recommended blood pressure goal of less than 130/80 mm Hg for patients with diabetes.
Other antihypertensives such as beta-blockers, calcium channel blockers, and diuretics lower blood pressure but do not affect the glomerular hyperfiltration. Therefore, these antihypertensive classes are not first-line agents but may be considered for combination use if patients do not achieve their blood pressure goal with ACE inhibitor or ARB monotherapy or if they do not tolerate ACE inhibitors or ARBs.
Key Point
- Prevention of diabetic nephropathy involves reducing the patient’s risk of developing microalbuminuria, which is associated with progressive chronic kidney disease and cardiovascular events.
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