What is the management for an elevated Albumin to Creatinine (A/C) ratio indicating Impaired renal function?

Management of Elevated Albumin to Creatinine (A/C) Ratio

For patients with elevated albumin to creatinine ratio indicating impaired renal function, the cornerstone of management is treatment with an ACE inhibitor or angiotensin receptor blocker (ARB), along with optimization of blood pressure and glucose control. 1

Classification of Albuminuria

Albuminuria is classified according to the following categories:

• A1 (Normal to Mildly Increased): uACR <30 mg/g (<3 mg/mmol) 1
• A2 (Moderately Increased): uACR 30-299 mg/g (3-29 mg/mmol) 1
• A3 (Severely Increased): uACR ≥300 mg/g (≥30 mg/mmol) 1

Management Algorithm Based on Albuminuria Level

For A1 (Normal to Mildly Increased, <30 mg/g)

• Monitor annually in patients with diabetes 1
• ACE inhibitors or ARBs are NOT recommended for primary prevention in normotensive patients with normal UACR 1
• Recent research suggests that even within the normal range, UACR >10 mg/g may predict CKD progression in type 2 diabetes 2
• Consider more frequent monitoring if UACR is in the high-normal range (15-29 mg/g) 3

For A2 (Moderately Increased, 30-299 mg/g)

• Initiate ACE inhibitor or ARB therapy 1
• Optimize blood pressure control (target <140/90 mmHg) 1
• Optimize glycemic control in diabetic patients 1
• Monitor serum creatinine and potassium when starting ACE inhibitors, ARBs, or diuretics 1
• Continue monitoring UACR to assess progression 1

For A3 (Severely Increased, ≥300 mg/g)

• Strongly recommended to use ACE inhibitor or ARB therapy 1
• Target reduction of ≥30% in urinary albumin to slow CKD progression 1
• Monitor serum creatinine and potassium closely 1
• Consider referral to nephrology, especially if eGFR <30 mL/min/1.73 m² 1

Comprehensive Management Approach

Blood Pressure Management

• Optimize blood pressure control to reduce risk or slow progression of diabetic kidney disease 1
• Blood pressure targets should be individualized, but generally <140/90 mmHg 1
• Even mild elevations in blood pressure (≥130/85 mmHg) are associated with increased albumin excretion 4

Glycemic Control

• Optimize glucose control to reduce risk or slow progression of diabetic kidney disease 1
• HbA1c targets should be individualized based on patient factors 1

Medication Management

• ACE inhibitors or ARBs are first-line therapy for albuminuria 1
• Losartan has been shown to reduce proteinuria by an average of 34% and slow the decline in glomerular filtration rate by 13% in patients with type 2 diabetes and nephropathy 5
• Monitor for increased creatinine (up to 20% increase may be acceptable) and hyperkalemia when starting RAS blockers 1
• Do not discontinue RAS blockade for minor increases in serum creatinine (≤30%) in the absence of volume depletion 1

Dietary Considerations

• For people with diabetic kidney disease, protein intake should not be reduced below the recommended daily allowance of 0.8 g/kg/day 1
• For patients on dialysis, higher levels of dietary protein intake should be considered 1

Monitoring

• At least annual assessment of urinary albumin and eGFR in patients with diabetes 1
• Be aware of high biological variability in UACR measurements (>20% between measurements) 6
• Multiple specimens (2-3) collected within 3-6 months should be abnormal before confirming diagnosis 1
• Factors that can temporarily elevate UACR include exercise within 24 hours, infection, fever, heart failure, marked hyperglycemia, menstruation, and hypertension 7

When to Refer to Nephrology

• eGFR <30 mL/min/1.73 m² 1
• Uncertainty about etiology of kidney disease 1
• Difficult management issues 1
• Rapidly progressing kidney disease 1
• Presence of nephrotic syndrome or active urinary sediment 1

Pitfalls and Caveats

• Single UACR measurements can be misleading due to high day-to-day variability; confirm with repeat testing 6
• Do not rely solely on dipstick tests for proteinuria as they may miss early albuminuria 1
• Albuminuria occurs on a continuum, and risk increases even within the "normal" range 8, 3
• Avoid using terms like "microalbuminuria" and "macroalbuminuria" as they are outdated 1
• Be aware that spontaneous remission of moderately increased albuminuria can occur in up to 40% of patients with type 1 diabetes 1