Research Update: Does FIV play a role in the development of chronic kidney disease in cats?
In people, an association between human immunodeficiency virus (HIV) retroviral infection and renal failure secondary to glomerular disease is well-established. Previous studies comparing cats infected with feline immunodeficiency virus (FIV) with uninfected cats have demonstrated that FIV-infected animals are more likely to be azotemic and proteinuric.1 However, no study has specifically evaluated the prevalence of FIV infection in cats with idiopathic CKD, which the authors of this study hypothesized would be higher than in nonazotemic cats.
The authors prospectively enrolled cats presenting to two Australian veterinary hospitals over a 14-month period in this case-control study; this study period was prior to the introduction of the FIV vaccine to Australia, so false positive diagnosis of FIV due to vaccine-induced circulating antibodies was minimal. CKD was defined as concurrent serum creatinine concentration > 2 mg/dl (180 mol/L) and urine specific gravity < 1.035. The authors excluded any cats for which a presumptive or definitive cause of renal disease had been identified.Age, sex, breed, creatinine concentration, urine specific gravity, and results of FIV antibody testing were collected from 73 cats with CKD and from 69 control cats with no laboratory evidence of CKD evaluated at the same hospitals over the same time period. The control group included both sick and healthy cats, and any cat with a concurrent medical condition that may be associated with kidney damage (e.g. urinary tract infection, hypokalemia, hyperthyroidism) was excluded. FIV antibody testing was performed using the anti-Gp40 antibody test, and a single positive result was considered diagnostic for FIV infection.
Twelve of 73 cats with CKD (16.4%) and six of 69 cats in the control group (8.7%) were infected with FIV based on antibody testing. Multivariable regression analysis revealed that FIV infection was significantly associated with CKD in cats less than 11 years of age, with an odds ratio of 10 that cats in this age group would be infected with FIV if CKD had been diagnosed. However, the presence of CKD in cats 11 years of age or older was not associated with a change in odds of infection with FIV.