Feline chronic kidney disease (CKD) has highly variable patterns of progression. Objective methods to differentiate cats with stable and progressive CKD are lacking. This retrospective study aimed to determine a slope cutoff for reciprocal of creatinine (creatinine -1 ) vs time to objectively differentiate stable and progressive feline CKD, and identify risk factors for CKD progression within 3 months of CKD diagnosis. Euthyroid client-owned cats with azotaemic CKD (n = 321) were included in this study. CKD cats that demonstrated stable (365 days (n = 194) were identified and the reciprocal plot of plasma creatinine vs time (creatinine -1 plot) from these cats was used to determine a cutoff to differentiate stable from progressive CKD. Risk factors for progressive CKD, including response to 3 months of standard treatment, were explored by binary logistic regression. Variables associated with mortality were evaluated using Cox regression. A slope cutoff of -9 . 5×10 -5 L/μmol/month (-8.4×10 -3 dL/mg/month) for creatinine -1 plot distinguished stable (n = 231) vs progressive (n = 90) CKD cats. Baseline plasma log-transformed fibroblast growth factor-23 (lnFGF-23), albumin concentrations, advancing age, and slope of creatinine -1 , phosphate and body weight within the first 84 days of CKD diagnosis were independent risk factors for progression. Progressive cats had shorter median survival time 95% CI than non-progressive cats (287 246–354 vs 894 812–1052 days; P < 0.001). Overall, cats with stable and progressive CKD can be distinguished using slope of creatinine -1 plot. Risk factors identified may facilitate early detection of cats with progressive CKD. • There are currently no consensus guidelines defining progression in chronic kidney disease in cats • An inverse creatinine (creatinine -1 ) slope cutoff of -9.5×10 -5 L/μmol/month (-8.4×10 -3 dL/mg/month) distinguished cats with stable vs progressive chronic kidney disease. • CKD cats with higher plasma fibroblast growth factor-23 (FGF-23), lower albumin concentrations, advancing age, and steeper slope of creatinine -1 , phosphate and body weight within the first 84 days of CKD diagnosis were independent risk factors for progression. • Cats with progressive CKD had a significantly shorter survival time, with a mortality rate of 63% within 365 days of diagnosis.
Tang et al. (Thu,) studied this question.