Improving on the Assessment of Kidney Health

The content below is taken from a recent article in the Journal of the American Society of Nephrology and looks so ways that can potentially improve the assessment of kidney disease and it's progression.

The current assessment of kidney health relies on eGFR and albuminuria and has served the nephrology community well. However, there is a pressing need to improve this assessment to better identify early kidney injury and determine optimal treatments for specific patients. On critical evaluation of current kidney health assessment, three limitations stand out: (1) the lack of an index of tubular function, (2) reliance on a single urinary biomarker, and (3) assessment based solely on static testing. In this Perspective, we propose that kidney health assessment could be enhanced by integrating urinary biomarkers that reflect tubular function and using dynamic testing methods.

Tubular injury is increasingly recognized as a driving force for kidney disease progression, and most kidney-protective drugs target the kidney tubule. Beyond chronic kidney disease (CKD) progression, tubular biomarkers may also play a role in interstitial nephritis, post-transplant monitoring, drug dosing, and kidney diseases with limited therapeutic options, such as acute kidney injury (AKI) and AKI-CKD transition. Thus, there is a strong pathophysiologic and clinical rationale to include tubular function in kidney health assessment and develop a severity grading system for tubular dysfunction. Urinary biomarkers can effectively capture changes in tubular function or the secretion profile of tubular epithelial cells. Although tubular biomarkers for CKD have not yet achieved widespread clinical use, those that have been identified correlate with clinically significant outcomes irrespective of eGFR and albuminuria.

Assessing tubular function can provide valuable insights not only into kidney disease but also into cardiovascular and cognitive health. The clinical application of tubular biomarkers requires them to demonstrate minimal biologic and analytical variability, fill a diagnostic or prognostic gap, or guide treatment, all while remaining cost-effective. Integrating tubular biomarkers into clinical trials would be a logical next step to expedite their implementation. In addition, if tubular stress tests outperform static ones, the added workload would be justified. The ultimate paradigm shift would be to expand the current CKD classification (C, G, A) by adding a fourth character, T, for tubular function.

Beckmann, Sebastian B.1; Salib, Madonna1; Fenton, Robert A.2; Hoorn, Ewout J.1. Toward Assessment of Tubular Function in Kidney Disease. Journal of the American Society of Nephrology ():10.1681/ASN.0000000705, March 20, 2025. | DOI: 10.1681/ASN.0000000705