Low serum albumin and elevated blood urea nitrogen-to-albumin and creatinine-to-albumin ratios are associated with mortality in dogs.

BAR, CAR, and low albumin are stronger mortality predictors than creatinine alone in hospitalized dogs.

This retrospective, single-center study evaluated the prognostic utility of two novel biochemical ratios—blood urea nitrogen-to-albumin ratio (BAR) and creatinine-to-albumin ratio (CAR)—in 327 dogs presenting to a referral hospital between September 2022 and June 2025. Dogs were stratified by outcome into survivors (n=235) and nonsurvivors (n=92). Nonsurvivors demonstrated significantly elevated BAR (median 6.62 vs. 5.01) and CAR (0.36 vs. 0.29), lower serum albumin (2.9 vs. 3.2 g/dL), and higher BUN (18.8 vs. 16.0 mg/dL) compared to survivors. Survival analysis identified hypoalbuminemia as the strongest independent predictor of mortality, with a hazard ratio of 2.01 (95% CI, 1.32–3.07). Elevated BAR, BUN, and CAR were also associated with poor survival; however, creatinine alone did not predict outcome. A random forest machine learning model demonstrated excellent discriminatory performance with an AUC of 0.998, specificity of 100%, and sensitivity of 71.7%. Notably, BAR, CAR, BUN, and albumin collectively outperformed creatinine as mortality predictors. These ratios are inexpensive, easily calculated from routine biochemical panels, and may offer additive prognostic value beyond individual analytes. The authors suggest these biomarkers warrant prospective, multicenter validation to confirm generalizability and establish clinical reference thresholds for routine use in critically ill and hospitalized canine patients.

This summary was distilled by AI and may occasionally misinterpret data. Confirm critical details with the primary literature before clinical application.