A 58-year-old man with type 2 diabetes mellitus comes to the physician for a follow-up appointment. His other medical problems include obesity and chronic kidney disease with a baseline creatinine of 1.5 mg/dL and urine protein excretion of 1100 mg/day. He has failed to lose weight despite diet adjustments and aerobic exercise. The patient takes insulin daily. His blood pressure is 140/89 mm Hg and his pulse is 83/min. Body mass index is 30 kg/m². He is started on lisinopril 5 mg daily.
The patient returns for a follow-up appointment 2 weeks later and reports feeling well. His blood pressure is 133/85 mm Hg. Repeat testing shows creatinine of 1.8 mg/dL and potassium of 4.8 mEq/L.
Which of the following is the best next step in management of this patient?

Question

Quizplus · Accepted Answer

This patient presents for management of diabetic nephropathy (ie, albuminuria of >300 mg/day or >300 mg/g creatinine on random urine sample). In addition to strict glycemic control and good blood pressure control (goal <140/90 mm Hg), inhibition of the renin-angiotensin-aldosterone system is a staple of therapy. Important side effects of angiotensin-converting-enzyme (ACE) inhibitor and angiotensin II receptor blocker (ARB) therapy include an expected initial decrease in glomerular filtration rate (GFR) from reduced renal capillary pressure (due to greater relaxation of the efferent arteriole) and possible rise in serum potassium from reduced levels of aldosterone. These side effects should be monitored closely, especially at the outset of therapy or during dose titration. A rise in serum creatinine of up to 30%-35% from baseline is acceptable and should not cause discontinuation of therapy (Choice C). Moderate elevations in serum potassium (<5.1-5.5 mEq/L) above normal limits should lead to dose reductions, and more severe elevations that cannot be managed with diuretics warrant discontinuation of therapy. < (Choice A) Studies examining the effects of combining ARB and ACE inhibitor therapy have demonstrated no significant benefits over monotherapy. However, they have shown an increase in adverse events, including higher rates of acute kidney injury requiring dialysis, hospitalization, severe hyperkalemia, and hypotension. (Choice D) Although good blood pressure control (goal <140/90 mm Hg) is associated with a number of improved outcomes in patients with diabetes and diabetic nephropathy, ACE inhibitor or ARB therapy is preferred over calcium channel blockers due to the additional renal protective effects. (Choice E) Current guidelines do not prefer ARB over ACE inhibitor therapy unless a patient is unable to tolerate an ACE inhibitor (eg, cough). Both classes of medications have similar reductions in GFR and elevations in serum potassium. Educational objective: Angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers are first-line medications for the management of diabetic nephropathy due to their renal protective effects. Both therapies are associated with a rise in serum creatinine of up to 30%-35% from baseline; this is acceptable and should not cause discontinuation of therapy. __________ References: Current concepts in the management of diabetic nephropathy. (http://www.ncbi.nlm.nih.gov/pubmed/24218418) Diabetic nephropathy: common questions. (http://www.ncbi.nlm.nih.gov/pubmed/16035688) Management of diabetic nephropathy. (http://www.ncbi.nlm.nih.gov/pubmed/11385086)

A 58-Year-Old Man with Type 2 Diabetes Mellitus Comes to the Physician