Development and implementation of a novel immune thrombocytopenia bleeding score for dogs

Abstract

BackgroundA method of quantifying clinical bleeding in dogs with immune thrombocytopenia (ITP) is needed because ITP patients have variable bleeding tendencies that inconsistently correlate with platelet count. A scoring system will facilitate patient comparisons and allow stratification based on bleeding severity in clinical trials.Hypothesis/ObjectivesTo develop and evaluate a bleeding assessment tool for dogs, and a training course for improving its consistent implementation.AnimalsClient‐owned dogs (n = 61) with platelet counts <50,000/μL; 34 classified as primary ITP, 17 as secondary ITP, and 10 as non‐ITP.MethodsA novel bleeding assessment tool, DOGiBAT, comprising bleeding grades from 0 (none) to 2 (severe) at 9 anatomic sites, was developed. Clinicians and technicians completed a training course and quiz before scoring thrombocytopenic patients. The training course was assessed by randomizing student volunteers to take the quiz with or without prior training. A logistic regression model assessed the association between training and quiz performance. The correlation of DOGiBAT score with platelet count and outcome measures was assessed in the thrombocytopenic dogs.ResultsClinicians and technicians consistently applied the DOGiBAT, correctly scoring all quiz cases. The odds of trained students answering correctly were higher than those of untrained students (P < .0001). In clinical cases, DOGiBAT score and platelet count were inversely correlated (r s = −0.527, P < .0001), and DOGiBAT directly correlated with transfusion requirements (r s = 0.512, P < .0001) and hospitalization duration (r s = 0.35, P = .006).Conclusions and Clinical ImportanceThe DOGiBAT and assessment quiz are simple tools to standardize evaluation of bleeding severity. With further validation, the DOGiBAT may provide a clinically relevant metric to characterize ITP severity and monitor response in treatment trials.

Immune thrombocytopenia (ITP): Pathophysiology update and diagnostic dilemmas

“…In a pilot study of ITP, increasing DOGiBAT scores, which denoted more severe clinical signs, were found in dogs with more severe thrombocytopenia. However, unlike platelet counts, the DOGiBAT score at admission correlated with transfusion requirements and the duration of hospital stay . Although further validation studies are required, these preliminary results suggest that DOGiBAT scoring could prove clinically useful as a prognostic indicator.…”

“…As a result of its complex disease pathogenesis and the variable contribution of many different immunologic players in individual patients, ITP is a clinically heterogeneous disease in both people and dogs . Not all ITP patients bleed and platelet count alone does not reliably predict bleeding outcomes .…”

“…In a recent study of 61 thrombocytopenic dogs, 57% of dogs were determined to have primary ITP, 28% secondary ITP due to lymphoid/myeloid neoplasia (9.8%), infectious disease (9.8%), liver disease (5%), or drug exposure (3%), and 15% had non‐immune thrombocytopenia attributed to bone marrow aplasia or consumptive coagulopathy . Investigations for secondary causes of ITP include medication history review, blood chemistry panel and urinalysis for systemic disease, vector‐borne disease screening, and imaging to rule out neoplasia.…”

“…In several studies, platelet counts were significantly lower in dogs with primary thrombocytopenia than dogs with other causes of thrombocytopenia . Even when comparing primary vs secondary ITP, thrombocytopenia was more severe in dogs with primary disease . Although platelet counts overlap, severe (<20 000 platelets/µL) thrombocytopenia is suggestive of primary ITP.…”

“…In addition to standardization, the metric aims to simplify data collection by categorizing bleeding manifestations into three anatomic sites (skin, mucosa, organ) and apply numeric scores based on the severity of hemorrhage. Similarly, “DOGiBAT,” a bleeding assessment tool based on the human ITP Bleeding Scale, has recently been developed for classification of bleeding severity in canine ITP with the goal of facilitating patient stratification and monitoring response to therapy across institutions and treatment trials . The DOGiBAT scoring system assigns bleeding severity grades at nine anatomic sites.…”