Acute on chronic kidney disease in cats: Etiology, clinical and clinicopathologic findings, prognostic markers, and outcome

Background: Chronic kidney disease (CKD) and acute decompensation of CKD (ACKD) are common in cats. Objectives: To characterize the etiology, clinical and clinicopathologic findings, and the short- and long-term prognosis of feline ACKD. Animals: One hundred cats with ACKD. Methods: Retrospective study, search of medical records for cats with ACKD. Results: Common clinical signs included anorexia (85%), lethargy (60%), weight loss (39%), and vomiting (27%). Suspected etiologies included ureteral obstruction (11%), renal ischemia (9%), pyelonephritis (8%), others (6%), or unknown (66%). Hospitalization duration was longer in survivors versus nonsurvivors (median = 7 days, range = 2-26 versus median = 3 days, range = 2-20, respectively, P <.001). The survival rate to discharge was 58%. Age, serum creatinine, urea, and phosphorous concentrations were higher and venous blood pH was lower in nonsurvivors. However, only serum phosphorus remained associated with the short-term outcome in the multivariable model (P =.02; 95% confidence interval = 1.03-1.39). Survivors had a median survival time of 66 days after discharge. Serum creatinine concentrations at presentation as well as at discharge were associated with long-term survival (P <.002 for both). Conclusions: The short-term prognosis of ACKD is comparable to acute kidney injury, while the long-term prognosis is guarded.