Predicting survival in dogs with immune-mediated hemolytic anemia

Abstract

BACKGROUND: Outcome prediction in dogs with immune-mediated hemolytic anemia (IMHA) is challenging and few prognostic indicators have been consistently identified. OBJECTIVES: An online case registry was initiated to: prospectively survey canine IMHA presentation and management in the British Isles; evaluate 2 previously reported illness severity scores, Canine Hemolytic Anemia Score (CHAOS) and Tokyo and to identify independent prognostic markers. ANIMALS: Data from 276 dogs with primary IMHA across 10 referral centers were collected between 2008 and 2012. METHODS: Outcome prediction by previously reported illness-severity scores was tested using univariate logistic regression. Independent predictors of death in hospital or by 30-days after admission were identified using multivariable logistic regression. RESULTS: Purebreds represented 89.1% dogs (n = 246). Immunosuppressive medications were administered to 88.4% dogs (n = 244), 76.1% (n = 210) received antithrombotics and 74.3% (n = 205) received packed red blood cells. Seventy-four per cent of dogs (n = 205) were discharged from hospital and 67.7% (n = 187) were alive 30-days after admission. Two dogs were lost to follow-up at 30-days. In univariate analyses CHAOS was associated with death in hospital and death within 30-days. Tokyo score was not associated with either outcome measure. A model containing SIRS-classification, ASA classification, ALT, bilirubin, urea and creatinine predicting outcome at discharge was accurate in 82% of cases. ASA classification, bilirubin, urea and creatinine were independently associated with death in hospital or by 30-days. CONCLUSIONS AND CLINICAL IMPORTANCE: Markers of kidney function, bilirubin concentration and ASA classification are independently associated with outcome in dogs with IMHA. Validation of this score in an unrelated population is now warranted.