Evaluation of blood urea nitrogen concentration and anorexia as predictors of nonsurvival in client-owned rabbits evaluated at a veterinary referral center.

To determine the prognostic relevance of BUN concentration in client-owned rabbits evaluated at a veterinary referral center. 246 healthy or clinically ill client-owned rabbits with BUN concentrations measured at a veterinary referral center. In a retrospective cohort study design, medical records of rabbits were retrieved, and data were collected on BUN concentration (exposure variable of interest) and other variables, including outcome (survival status at 15 days after BUN concentration measurement). Univariate, multivariate, and subgroup analyses were performed to identify variables associated with outcome. BUN concentrations ranged from 6.5 to 251.1 mg/dL (median, 18.7 mg/dL). Univariate analysis revealed that the risk of nonsurvival over the 15-day period for rabbits with a high BUN concentration (≥ 23.3 mg/dL) was 33% higher (relative risk, 1.33; 95% confidence interval [CI], 1.06 to 1.69) than that for rabbits with unremarkable BUN values. Subgroup analysis revealed that for rabbits with anorexia, a high (vs unremarkable) BUN concentration was associated with an increased risk of nonsurvival (relative risk, 1.69; 95% CI, 1.05 to 2.71). In the final multivariate model that controlled for age, sex, and appetite (anorexia vs no anorexia), the odds of nonsurvival for rabbits with BUN values > 24.74 mg/dL were 3 times that for rabbits with BUN values < 14.00 mg/dL (OR, 2.92; 95% CI, 1.29 to 6.58). Results indicated that a high BUN concentration increased the risk of nonsurvival over a 15-day period for client-owned rabbits, particularly those with anorexia. Blood urea nitrogen concentration should be used together with other clinical indicators to provide prognostic information for rabbits receiving veterinary care.