Treatment of Microalbuminuria
Confirmed microalbuminuria should be treated with an ACE inhibitor titrated to normalize albumin excretion, regardless of blood pressure status. 1, 2
Confirming the Diagnosis
Before initiating treatment, confirm microalbuminuria with 2 out of 3 abnormal urine specimens collected over 3-6 months, as day-to-day variability is significant. 2, 3 Use a random spot urine sample measuring albumin-to-creatinine ratio (30-299 mg/g creatinine defines microalbuminuria). 2, 3 Avoid testing during menstruation, after vigorous exercise, or during acute illness, as these falsely elevate results. 4
Pharmacologic Treatment Algorithm
Step 1: Initiate ACE Inhibitor Therapy
Start an ACE inhibitor as first-line therapy for all patients with confirmed microalbuminuria, even if normotensive. 1, 2, 3 This recommendation applies to both type 1 and type 2 diabetes, as ACE inhibitors delay progression to macroalbuminuria beyond their blood pressure-lowering effects. 2
Titrate the ACE inhibitor dose to normalize microalbumin excretion if possible. 1, 2
If ACE inhibitors are not tolerated (typically due to cough), substitute an ARB. 2, 3
Monitor serum creatinine and potassium levels when initiating therapy to detect hyperkalemia. 2, 3
Step 2: Optimize Blood Pressure Control
Target blood pressure <130/80 mmHg in all patients with diabetes or kidney disease. 2, 3, 5
If blood pressure targets are not achieved with ACE inhibitors or ARBs alone, add additional antihypertensive agents such as non-dihydropyridine calcium channel blockers, β-blockers, or diuretics. 2, 3
Step 3: Optimize Glycemic Control
- Target HbA1c <7% to reduce risk and slow progression of nephropathy. 2, 3 Intensive glycemic control reduces the development of microalbuminuria by 34-43% in type 1 diabetes and 24% in type 2 diabetes. 1
Dietary Modifications
Restrict protein intake to 0.8 g/kg body weight/day (approximately 10% of daily calories). 2, 4 This modest reduction significantly improves glomerular filtration rate and reduces albumin excretion. 4
Limit saturated fat to 7% of total energy intake and dietary cholesterol to 200 mg/day. 4
Consider replacing animal protein with plant protein sources for additional benefits. 4
Monitoring Response to Therapy
Monitor microalbumin excretion every 3-6 months to assess treatment response. 2, 3 A reduction in albuminuria of ≥30% indicates positive response to therapy. 2
Measure serum creatinine at least annually to estimate GFR and stage CKD if present. 2, 3
Continue monitoring serum potassium levels when using ACE inhibitors or ARBs. 2, 3
Critical Caveats
ACE inhibitors and ARBs are contraindicated in pregnancy and should be used with caution in patients with advanced renal insufficiency due to hyperkalemia risk. 2 Consider nephrologist referral when GFR falls below 60 ml/min/1.73 m² or when difficulties occur managing hypertension or hyperkalemia. 2, 3
The evidence strongly supports that intervention at the microalbuminuria stage preserves GFR and reduces cardiovascular mortality. 6, 7 Regression to normoalbuminuria rarely occurs without intensive treatment, making early aggressive intervention essential. 7