Research overview: proteinuria as a prognostic factor in feline CKD

The degree of urinary protein loss, assessed by the urine protein-to-creatinine ratio, is an important prognostic indicator in feline CKD, with higher proteinuria associated with faster progression and shorter survival. This recognition led IRIS to incorporate proteinuria substaging and to recommend antiproteinuric interventions such as renin-angiotensin system inhibitors in proteinuric cats. This overview compiles the prognostic literature rather than one source, describing how proteinuria reflects glomerular and tubular injury, why reducing it is a therapeutic target, and how monitoring the protein-to-creatinine ratio guides treatment intensity. It matters because proteinuria is both a marker of severity and a modifiable risk factor, making its measurement and management a practical part of slowing disease and refining prognosis in affected cats.