From the Guidelines
The workup for elevated albumin/creatinine ratio (ACR) should begin with confirmation of the abnormal result through repeat testing, ideally with a first-morning urine sample, as recommended by the most recent guidelines 1. An ACR ≥30 mg/g indicates albuminuria, with 30-300 mg/g classified as moderately increased and >300 mg/g as severely increased albuminuria, according to the latest classification system 1. After confirmation, a comprehensive evaluation should include:
- A complete history and physical examination
- Blood pressure measurement
- Assessment of glycemic control in diabetic patients
- Serum creatinine with estimated glomerular filtration rate (eGFR)
- Urinalysis with microscopic examination
- Renal ultrasound Additional testing may include serum albumin, complete blood count, electrolytes, and urine protein electrophoresis if indicated. For patients with diabetes or hypertension, the focus should be on optimizing blood pressure control (target <130/80 mmHg) using ACE inhibitors or ARBs as first-line agents, and improving glycemic control in diabetics, as suggested by recent studies 1. Referral to nephrology is warranted for patients with rapidly declining kidney function, ACR >300 mg/g, hematuria, or other concerning findings, as recommended by the latest guidelines 1. The significance of elevated ACR lies in its strong association with increased cardiovascular risk and progression of kidney disease, as albumin leakage into urine reflects endothelial dysfunction and glomerular damage, highlighting the importance of early detection and management 1.
From the Research
Workup for Elevated Albumin/Creatinine Ratio
- The workup for an elevated albumin/creatinine ratio typically involves assessing the patient's risk factors for cardiovascular and renal disease, as albuminuria is a known risk marker for these conditions 2.
- Screening methods for albuminuria include microalbumin-specific dipsticks and urinary albumin:creatinine ratio determination from a spot urine sample, which are suitable for use in primary care settings 2.
- The relationship between albuminuria and risk is continuous and linear, similar to that of blood pressure and cardiovascular risk, and evidence supports increased risk even at levels traditionally considered within normal limits 2.
- In patients with diabetes, hypertension, and chronic kidney disease, routine annual screening can detect changes in urine albumin excretion and improve timely identification of albuminuria 2.
Management of Albuminuria
- Cornerstones of albuminuria treatment include risk factor management, ongoing monitoring, and the use of renin-angiotensin-aldosterone system (RAAS)-blocking agents in patients with hypertension, chronic kidney disease, or diabetes 2.
- Both angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) have demonstrated utility in reducing albuminuria, with the combined use of an ACE inhibitor and ARB being considered in certain cases 2.
- Sodium-glucose cotransporter 2 (SGLT-2) inhibitors have also been shown to have renoprotective effects and reduce albuminuria in patients with diabetes mellitus 3.
Prognostic Value of Albuminuria
- Elevated urine albumin-to-creatinine ratio is an independent risk factor for new-onset heart failure in patients with type 2 diabetes, with increasing ratios associated with a progressively increased risk of heart failure 4.
- The addition of urine albumin-to-creatinine ratio to established heart failure risk models can improve the prediction of heart failure risk in community-based patients with type 2 diabetes 4.
- Albuminuria is also associated with an increased risk of adverse cardiovascular and renal outcomes, and its measurement can inform the prescription of renin-angiotensin system blockade 5.