Short-term mortality prediction based on biochemical blood markers in azotemic cattle with renal disease

Renal disease in cattle is often suspected based on urinalysis and blood biochemical analysis, but prognostic biomarkers for survival are lacking.

Identify blood and urine biomarkers predicting mortality or discharge in azotemic cattle.

Thirty-four azotemic adult cattle referred to the Clinic for Cattle of the National Veterinary School of Toulouse.

In our prospective cohort study, renal disease was suspected based on clinical signs and azotemia (plasma creatinine concentration > 228 μmol/L and urea concentration > 5 mmol/L) and confirmed by urinalysis or ultrasonography. When death or euthanasia occurred, confirmation was obtained by gross and histologic examination. To construct a decision tree for short-term prognosis, additional biochemical and cytological biomarkers were measured in urine and blood samples collected at hospitalization. Outcomes were defined as favorable (discharge) or unfavorable (death). Correlation analyses, univariate and multivariate statistics, receiver operating characteristic curves, and decision tree modeling were performed.

Thirteen cattle survived and 21 died or were euthanized. Mortality was associated with higher plasma symmetric dimethylarginine (SDMA), creatinine, and urea concentrations, as well as hypocalcemia, hypochloremia, and lower hematocrit. Creatinine, SDMA, chloride, and albumin were the most consistent predictors of outcome. A decision tree combining creatinine and SDMA achieved 87.5% accuracy. Animals with plasma creatinine concentration < 605 μmol/L and SDMA < 33 μg/dL had the highest probability of survival.

Plasma creatinine, urea, SDMA, chloride, and albumin concentrations are promising short-term prognostic biomarkers in azotemic cattle. Combined SDMA and creatinine assessment may assist clinical decision-making.