Renal Disease in Cats Infected with Feline Immunodeficiency Virus

Background: Feline immunodeficiency virus (FIV) and human immunodeficiency virus (HIV) infection cause similar clinical syndromes of immune dysregulation, opportunistic infections, inflammatory diseases, and neoplasia. Renal disease is the 4th most common cause of death associated with HIV infection. Objective: To investigate the association between FIV infection and renal disease in cats. Animals: Client-owned cats (153 FIV-infected, 306 FIV-noninfected) and specific-pathogen-free (SPF) research colony cats (95 FIV-infected, 98 FIV-noninfected). Methods: A mixed retrospective/prospective cross-sectional study. Blood urea nitrogen (BUN), serum creatinine, urine specific gravity (USG), and urine protein: creatinine ratio (UPC) data were compared between FIV-infected and FIV-noninfected cats. In FIV-infected cats, total CD4+ and CD8+ T lymphocytes were measured using flow cytometry, and CD4+: CD8+ T lymphocyte ratio was calculated. Renal azotemia was defined as a serum creatinine >= 1.9 mg/dL with USG <= 1.035. Proteinuria was defined as a UPC > 0.4 with an inactive urine sediment. Results: Among the client-owned cats, no association was detected between FIV infection and renal azotemia (P = .24); however, a greater proportion of FIV-infected cats were proteinuric (25.0%, 16 of 64 cats) compared to FIV-noninfected cats (10.3%, 20 of 195 cats) (P < .01). Neither neuter status nor health status were risk factors for proteinuria in FIV-infected cats, but UPC was positively correlated with the CD4+: CD8+ T lymphocyte ratio (Spearman's rho = 0.37, P = .01). Among the SPF research colony cats, no association was detected between FIV infection and renal azotemia (P = .21) or proteinuria (P = .25). Conclusions and Clinical Importance: Proteinuria but not azotemia was associated with natural FIV infection.