Checking for Protein in the Urine is Important in Patients with CKD

Many providers are using the chronic kidney disease stages paradigm to determine where patients stand to evaluate their risk of progressing toward end-stage kidney disease and the need for dialysis. Not enough providers are checking their patients for protein in the urine. Why is the evaluation of protein in the urine, also known as albuminuria, so important?

Patients who have chronic kidney disease, or CKD, have a higher risk of heart disease. They also have less kidney reserve as they approach stages 4-5, needing kidney dialysis sooner. Making matters worse, if a person with CKD has albumin in the urine, there is an increased risk of dying from kidney disease and heart disease. Please see the figure below which graphically describes the risk of progression to end-stage kidney disease based on your GFR and level of protein in the urine.

The chronic kidney disease stages heat map. Note in red that patients with stages 4 and 5 and severely increased urinary protein levels have a very high risk of disease progressing toward kidney replacement therapy also known as dialysis.

How do health care providers determine the amount of protein in the urine and classify it as either normal to very mildly increased urine protein, moderately increased urine protein, or severely increased urine protein? To determine risk, health care providers will order a urine albumin to creatinine ratio. We perform the test in the clinic. A 24-hour urine collection is not required. The results come back quickly. The information provided by the urine albumin to creatinine ratio is helpful for both patients with diabetes and for patients without diabetes.

If you have CKD and higher levels of protein in the urine, your risk over time is worse than if you do not have protein in the urine. The test provides more information besides risk. The test may alert the nephrologist that something grave is going on. For example, if you have very high levels of protein in the urine, what we call the nephrotic syndrome, the kidney provider may order a battery of tests to evaluate the cause of kidney disease further. In that setting, you may need a kidney biopsy.

Many providers appropriately focus on HbA1c or hemoglobin A1C in diabetes to assess for sugar control. That test is important to make sure your diabetes is under control. But regarding the kidneys, the albumin to creatinine ratio is more important.

So in summary, if you have chronic kidney disease, please make sure that your provider has checked the albumin to creatinine ratio besides the other essential studies. The albumin to creatinine value will help risk stratify your situation, telling the team how much danger the kidneys and the heart face in the future.