Serum uromodulin in dogs with chronic kidney disease

BACKGROUND: Serum uromodulin concentration has been described as a novel biomarker of chronic kidney disease (CKD) in humans but not dogs. OBJECTIVE: To evaluate the serum uromodulin concentration in dogs with CKD and assess its diagnostic performance in distinguishing dogs with CKD from healthy dogs. ANIMALS: Forty‐nine dogs with CKD (International Renal Interest Society [IRIS] Stage 1, n = 23; Stage 2, n = 20; Stage 3‐4, n = 6) and 25 healthy controls. METHODS: Prospective, observational study. Serum uromodulin concentration was measured using a canine‐specific enzyme‐linked immunosorbent assay (ELISA), and its correlation with conventional renal markers was analyzed. RESULTS: Serum uromodulin concentrations were significantly lower in the CKD group than in the control group (P < .001), but no significant difference was observed among stages of CKD. A negative correlation was observed between serum uromodulin concentration and conventional renal markers (blood urea nitrogen concentration, r = −.60, P < .0001; serum creatinine concentration, r = −.46, P < .0001; serum symmetric dimethylarginine concentration [SDMA], r = −.65, P < .0001). In receiver operating characteristic analysis, the area under the curve (AUC) of uromodulin (AUC, 0.97; 95% confidence interval [CI], 0.94‐1.00) was higher than that of SDMA (AUC, 0.87; 95% CI, 0.79‐0.95) for CKD diagnosis (P = .01). The AUC of uromodulin (AUC, 0.95; 95% CI, 0.89‐1.00) also was higher than that of SDMA (AUC, 0.72; 95% CI, 0.58‐0.87) in distinguishing dogs with Stage 1 CKD from controls (P = .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Serum uromodulin concentration is decreased in dogs with CKD. Thus, serum uromodulin may be a valuable diagnostic marker for CKD in dogs, particularly in identifying early‐stage CKD.