Noninvasive Test Identifies Patients at Risk for Kidney Disease Progression

Researchers have identified a simple, new, noninvasive way to identify patients at risk for progression of kidney disease. The test has important implications because although chronic kidney disease is a common medical problem worldwide, it is difficult to predict which patients are more likely to progress to end-stage disease and need aggressive management.

The test measures epidermal growth factor (EGF) in routine urine samples as an indicator of whether the patient is at risk of end-stage kidney disease. A decrease in urinary EGF protein is an early sign of diminishing kidney function and pinpoints the at-risk patient population. Not all patients with chronic kidney disease will progress to end-stage kidney disease and those who do tend to advance quickly and require dialysis or kidney transplant and are at an increased risk of death from cardiovascular disease.

Wenjun Ju, PhD, of the University of Michigan, and colleagues used four independent cohorts of hundreds of international patients to identify a marker of kidney disease progression. The investigators first identified EGF in biopsy tissue as being a molecule of interest in patients with chronic kidney disease. Then they validated that finding in urine samples from more than 940 patients with the disease, and were able to link decreased levels of EGF in urine to worsening kidney disease. Patients with low urinary EGF levels were found to be 4 times more likely to worsen than those who retained EGF function in their kidneys.

The standard technique now used to assess kidney disease is a kidney biopsy, which is costly, carries a low but significant health risk, and has limited ability to predict the future course of kidney disease.

Study coauthor Matthias Kretzler, MD, explained that urinary EGF can help patients in 2 important ways: “First, in clinical practice, it could be used to prioritize care to those patients most at risk of losing their kidney function. Second, and more immediately, using urinary epidermal growth factor levels will improve and speed up clinical trials,” he said in a statement. Enrolling only those likely to develop specific disease end points can reduce the number of people needing study and ensure the trial achieves an optimal mix of patients.

The researchers noted that urinary EGF has the potential to reduce trial costs by as much as 75%, as well as shorten the time until a medicine is widely available to all patients.