Background: Accumulation of renal injury contributes to the development of chronic kidney disease. Renal functional markers, including creatinine and symmetric dimethylarginine (SDMA), are insensitive to kidney injury. Urinary cystatin B (cysB) is a marker of renal injury independent of functional changes. Objective/Hypothesis: Evaluate effect of signalment and of renal functional markers on the likelihood of increased cysB in dogs and cats. Animals: Retrospective data study of 208,440 dog and 237,500 cat clinical samples with cysB, creatinine, and SDMA results and signalment information submitted to IDEXX Laboratories submitted from September 1, 2023 to September 1, 2024.
Methods: ORs for predicting the likelihood and probability of increased cysB were calculated using logistic regression. ORs were calculated with young animals (dogs 1-3 years, cats 1-6 years), medium-sized breeds (dog), male, and neutered animals as the reference groups.
Results: Increased cysB was more likely in adult (OR=1.47) and senior (OR=3.32) dogs, small (OR 1.3) and toy (OR=1.77) breeds, females (OR=1.16), and intact (OR=1.36) dogs. Increased SDMA (OR=3.89), increased creatinine (OR=3.11), and both (OR=15.3) were associated with high cysB (Figure 1). In cats, risk was higher in adults (OR=1.21), seniors (OR=1.90), females (1.11) and intact cats (1.27). Increased SDMA (OR=2.99) and concurrent SDMA and creatinine (OR=5.5) but not increased creatinine (OR=0.97) were associated with high cysB (Figure 2). Conclusions and Clinical Importance: Age, sex, and neuter status impact likelihood of increased cysB. Increased creatinine was only associated with high cysB risk in dogs but SDMA and concurrent increases predicted higher risk in both.
