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

Abstract

Background: A 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/objectives: To develop and evaluate a bleeding assessment tool for dogs, and a training course for improving its consistent implementation.

Animals: Client-owned dogs (n = 61) with platelet counts <50,000/μL; 34 classified as primary ITP, 17 as secondary ITP, and 10 as non-ITP.

Methods: A 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.

Results: Clinicians 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 importance: The 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.

Keywords: bleeding scale; daily canine bleeding assessment tool; immune-mediated thrombocytopenic purpura; platelets.

Figure 1

Sample slide from training course instructing the DOGiBAT user on how to correctly score cutaneous bleeding

Figure 2

Experimental design showing the 3 phases of this study

Figure 3

Box plots of platelet counts (A) and DOGiBAT scores (B) on admission in all dogs, dogs with PI, SI, and NI thrombocytopenia. In each case, the box represents the interquartile range, the horizontal line represents the median, and the whiskers represent the data range. *P = .034; †P = .003; ‡P = .021; §P = .01

Figure 4

Relationship between total DOGiBAT score and platelet count in all dogs on days of hospitalization where both a platelet count and DOGiBAT score were performed. There was a strong negative correlation between platelet count and DOGiBAT score in all dogs (r _s = −0.527, P < .0001)