Urinary Tubular Biomarkers for Chronic Kidney Disease

Rationale Chronic kidney disease (CKD) is a common and progressive condition that affects over 800 million people worldwide and is now one of the leading causes of mortality. The kidney consists of filters and tubules, but diagnosis of progressive CKD is currently based on filter function alone (estimated glomerular filtration rate (eGFR) and albuminuria). However, it is tubular injury that drives CKD progression, and it is the tubule that is targeted by recently developed kidney-protective treatments. We hypothesize that a high-throughput tubular test panel, consisting of urine supersaturation and urinary extracellular vesicle (uEV) biomarkers, improves the prediction of CKD progression thereby enabling the early initiation of kidney-protective treatment. Objective(s) To develop a high-throughput tubular test panel, consisting of urine supersaturation and uEV biomarkers, that improves the prediction of CKD progression. Study type Prospective diagnostic trial. Study population Adult patients with CKD stage G3 (eGFR 30-59 ml/min/1.73 m2). Methods Urine samples are already collected as part of the standard of care and will be divided for measurement of albuminuria (standard of care) and urine supersaturation and uEV biomarkers (this project). The performance of the tubular test panel will be analyzed by comparing it to that of the existing Kidney Failure Risk Equation. Burden and risks The diagnostic tests will be performed on a urine sample that is already collected as part of routine clinical care. Therefore, these diagnostic procedures do not pose an additional risk or burden. Recruitment and consent Participants will be recruited from the Department of Internal Medicine outpatient clinics. For all study participants written informed consent will be obtained. The informed consent will include the approval (yes/no) to store samples for secondary use.