What does an elevated albumin-to-creatinine ratio (ACR) indicate and how is it managed?

From the Guidelines

An elevated albumin-to-creatinine ratio (ACR) indicates kidney damage and is a key marker for chronic kidney disease, particularly diabetic nephropathy, with a normal ACR defined as <30 mg/g Cr, and high urinary albumin excretion defined as ≥30 mg/g Cr 1. The management of an elevated ACR involves confirming the elevation through repeated testing, as transient increases can occur due to various factors such as exercise, infection, fever, congestive heart failure, marked hyperglycemia, menstruation, and marked hypertension 1. Once confirmed, treatment focuses on addressing underlying causes and implementing kidney-protective strategies, including:

• First-line medications: ACE inhibitors (like enalapril 5-40 mg daily or lisinopril 10-40 mg daily) or ARBs (such as losartan 50-100 mg daily) to reduce proteinuria and slow kidney disease progression 1.
• Blood pressure control: below 130/80 mmHg.
• Tight glycemic control for diabetic patients: targeting HbA1c below 7%.
• SGLT2 inhibitors (empagliflozin 10-25 mg daily or dapagliflozin 5-10 mg daily) for significant kidney-protective benefits in both diabetic and non-diabetic kidney disease.
• Lifestyle modifications: sodium restriction to less than 2 grams daily, moderate protein intake (0.8 g/kg/day), regular exercise, smoking cessation, and weight management. Regular monitoring of ACR, estimated glomerular filtration rate (eGFR), and electrolytes is necessary to track disease progression and medication effects 1. Early nephrology referral is recommended for rapidly declining kidney function, ACR above 300 mg/g, or eGFR below 30 ml/min/1.73m² 1.

From the Research

Albumin-to-Creatinine Ratio (ACR) Indications and Management

• An elevated albumin-to-creatinine ratio (ACR) is an indicator of kidney damage and is associated with an increased risk of kidney failure, cardiovascular disease, and mortality 2, 3, 4, 5.
• The ACR is used to quantify proteinuria, which is the presence of excess proteins in the urine, and is a preferred method for diagnosing and monitoring chronic kidney disease (CKD) 2.
• Studies have shown that an elevated ACR is a strong predictor of kidney failure and mortality in patients with CKD, and that it can be used to risk-stratify patients and guide treatment decisions 2, 4, 5.

Diagnostic Accuracy and Testing

• The diagnostic accuracy of the ACR can be affected by various factors, including the method of measurement and the presence of other urinary abnormalities 6.
• Point-of-care (POC) urine dipstick testing can be used to detect albuminuria and other urinary abnormalities, but its sensitivity and specificity may vary depending on the population being tested 6.
• Repeat testing may not be necessary to diagnose CKD in patients with type 2 diabetes, as a single abnormal ACR result has been shown to have a high positive predictive value for CKD 3.

Management and Prognosis

• Elevated ACR levels are associated with an increased risk of cardiovascular mortality in patients with coronary artery disease, regardless of the presence of type 2 diabetes mellitus 4.
• The ACR is independently associated with mortality at all levels of estimated glomerular filtration rate (eGFR) in older adults with diabetes, and may be particularly helpful for risk stratification in this population 5.
• Management of elevated ACR levels typically involves lifestyle modifications, such as blood pressure control and diabetes management, as well as pharmacological interventions to reduce proteinuria and slow kidney disease progression.