Clinical findings, prognostic factors, and outcome of protein-losing nephropathy in cats: A retrospective study

Background: Primary glomerular disease resulting in protein-losing nephropathy (PLN) is an uncommon cause of chronic kidney disease in cats, yet is important to recognize because it warrants specific treatment that impacts outcome. Hypothesis/Objective: Characterize clinicopathologic findings, prognostic indicators, and short- (≤30 days) and long-term survival of cats with PLN. Animals: Thirty-seven cats with naturally occurring PLN. Methods: Medical records of cats with PLN admitted to a veterinary teaching hospital were retrospectively reviewed. Results: Median age was 3 years (range, 1.5-11.5 years) and 17/37 (46%) were males. Short-term survival was 57%. The estimated median survival time of all cats was 424 days (95% confidence interval [CI], 0-1098 days). Common clinical signs included lethargy (57%), edema (46%) and weight loss (35%). Edema was more common in short-term survivors compared with nonsurvivors (odds ratio [OR], 0.21; 95% CI, 0.05-0.86-20.4; P =.04). Serum creatinine concentration at presentation was negatively associated with long-term survival (OR, 1.3; 95% CI, 1.03-1.52; P =.01). Administration of immunosuppressive and antiproteinuric medications was more common among short-term survivors compared with nonsurvivors (18/20 [90%] vs 9/16 [56%]; OR, 7.0; 95% CI, 1.2-40.8; P =.05 and 17/20 [85%] vs 7/16 [44%]; OR, 7.3; 95% CI, 1.5-35.2; P =.01, respectively). Partial or complete remission was documented in 11/31 (36%) cats and was associated with both short (OR, 3.3; 95% CI, 1.7-6.5; P <.001) and long-term survival (P =.003). Conclusion and Clinical Importance: Cats with PLN have a guarded prognosis, but achieving remission improves outcome. Cats presented with edema rather than azotemia are more likely to respond to treatment.