Abstract:

Acute kidney injury (AKI) in cats is associated with high mortality, partially attributed to late recognition of the disease when using currently available markers. Feline chronic kidney disease (CKD) has a variable progression rate. This study aimed to evaluate the sensitivity and specificity of urinary heat shock protein-72 to urinary creatinine ratio (uHSP72:uCr) as a diagnostic and prognostic marker in feline AKI, and as a prognostic indicator in feline CKD. The study included 63 cats, divided into five groups: healthy controls (n=10), urethral obstruction (UO; n=7), CKD (n=15), AKI (16 cats) and acute decompensating CKD (ACKD; n=15). Median uHSP72:uCr (ng/mg) of healthy, UO, CKD, AKI and ACKD cats were 0.44 (range, 0.13–1.1), 1.96 (range, 0.64–11.9), 4.2ng/mg (range, 0.57–22.16), 3.2 (range, 0.42–10.91) and 7.0 (range, 1.2–20.96), respectively, and differed (P<0.001) among groups. uHSP72:uCr was significantly lower in the controls vs. the CKD, AKI and ACKD groups. Receiver operator characteristic analysis of uHSP72:uCr, including the AKI and control groups, showed an area under the curve of 0.93 (95% confidence interval, 0.84–1.00), indicating an excellent predictive performance for diagnosing AKI. A 0.54ng/mg cutoff point corresponded to 94% sensitivity and 70% specificity for diagnosing AKI. The median survival time of cats with CKD with low uHSP72:uCr was longer (P=0.036) than in those with high uHSP72:uCr (561 vs. 112 days, respectively). uHSP72:uCr is a highly sensitive, moderately specific marker of AKI in cats, and is associated with the survival of cats with CKD.