From the Guidelines
A high microalbumin/creatinine ratio in urine is a strong predictor of cardiovascular events and kidney damage, indicating the need for immediate intervention to prevent progression to more serious disease. This ratio measures the amount of albumin (a protein) that leaks into the urine when kidney function begins to decline, with normal values generally below 30 mg/g, and values between 30-300 mg/g considered moderately increased (previously called microalbuminuria) and above 300 mg/g severely increased (previously called macroalbuminuria) 1.
Key Points to Consider
- The presence of microalbuminuria, even below the currently used threshold values, predicts cardiovascular events and a continuous relationship between cardiovascular as well as non-cardiovascular mortality and urinary protein/creatinine ratios has been reported in several studies 1.
- Microalbuminuria can be measured from spot urine samples by indexing the urinary albumin concentration to the urinary creatinine concentration, and patients with microalbuminuria and proteinuria should be treated with an ACE inhibitor or angiotensin II receptor antagonist regardless of baseline BP 1.
- A high microalbumin/creatinine ratio is particularly significant in people with diabetes, hypertension, or other conditions that put stress on the kidneys, and early detection and management of kidney damage can significantly slow progression to more serious kidney disease.
Recommended Course of Action
- If a high ratio is found, the test should be repeated to confirm the finding, as temporary factors like fever, exercise, urinary tract infections, or high blood sugar can cause transient elevations.
- Healthcare providers will likely recommend steps to protect kidney function, including better control of blood pressure (often with medications like ACE inhibitors or ARBs), improved blood sugar control if diabetic, dietary changes (reducing sodium and protein intake), and lifestyle modifications such as weight loss, smoking cessation, and regular exercise.
From the Research
Definition of Microalbumin/Creatinine Ratio
- The microalbumin/creatinine ratio is a measure of the amount of albumin (a protein) in the urine compared to the amount of creatinine (a waste product) 2.
- This ratio is used to detect microalbuminuria, which is a sign of early kidney damage or disease 3.
Interpretation of High Microalbumin/Creatinine Ratio
- A high microalbumin/creatinine ratio indicates the presence of albuminuria, which is a risk factor for chronic kidney disease (CKD) progression, cardiovascular events, and mortality [(4,5)].
- The severity of albuminuria is categorized as follows:
- Normal: urine albumin/creatinine ratio < 30 mg/g
- Microalbuminuria: urine albumin/creatinine ratio 30-300 mg/g
- Macroalbuminuria: urine albumin/creatinine ratio > 300 mg/g [(3,6)]
- A high microalbumin/creatinine ratio is associated with an increased risk of CKD progression, especially in patients with diabetes, hypertension, or existing CKD [(4,5)].
Clinical Significance
- The presence of a high microalbumin/creatinine ratio warrants further evaluation and monitoring of kidney function, as well as assessment of cardiovascular risk factors [(2,3)].
- Patients with a high microalbumin/creatinine ratio may benefit from treatment with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) to slow CKD progression and reduce cardiovascular risk [(3,6)].