Prognostic utility of red blood cell distribution width-based ratios and their individual components for mortality prediction in dogs with acute pancreatitis

Introduction Prognostic assessment is critical in dogs with acute pancreatitis (AP). Composite biomarkers such as the red blood cell distribution width (RDW)-to-albumin ratio (RAR) and hemoglobin-to-RDW ratio (HRR) have shown prognostic value in human critical care but have not been evaluated in canine AP. Methods A retrospective cohort study was conducted in 80 dogs with AP and 10 healthy controls. The diagnostic and prognostic utility of admission HRR and RAR was compared with that of their individual components measured at admission (RDW, hemoglobin and albumin). Outcome was classified as survival or non-survival to hospital discharge. Receiver operating characteristic (ROC) curve analysis and multivariable logistic regression were performed. Results The overall mortality rate was 33.75%. Non-survivors presented with significantly lower hemoglobin, albumin and HRR values and significantly higher RDW values than survivors, whereas RAR did not differ between outcome groups. Among the variables evaluated, hemoglobin showed the highest discriminatory performance (AUC = 0.704; 95% CI: 0.583–0.812), followed by HRR (AUC = 0.669; 95% CI: 0.547–0.790), RDW (AUC = 0.663; 95% CI: 0.540–0.786), CAPCSI (AUC = 0.658) and albumin (AUC = 0.634; 95% CI: 0.506–0.757). In the multivariable model including age, hemoglobin, albumin, RDW and CAPCSI, only CAPCSI remained independently associated with survival (adjusted OR = 0.612; 95% CI: 0.403–0.929; p = 0.021). Discussion Integrating erythrocyte indices into composite ratios offered no clinical advantage over evaluating individual markers in dogs with acute pancreatitis. Among the laboratory variables assessed, hemoglobin showed the highest discriminatory performance, although its overall prognostic accuracy remained moderate. These findings suggest that erythrocyte-derived variables may serve as adjunctive prognostic markers in dogs with AP but should be interpreted alongside established clinical assessment.