Evaluation and validation of a revised VetCompass clinical grading tool for heat-related illness in dogs

The original VetCompass clinical grading tool for heat-related illness (HRI) in dogs was developed using general primary-care clinical records. Using two novel HRI emergency-care datasets from Vets Now clinics during 2022 and 2023, this current study aimed to firstly evaluate and revise the original tool, then to validate the revised tool. Evaluation of the original grading tool using 364 HRI cases treated during 2022 prompted three revisions; dyspnoea moved from Mild to Moderate grades, episodic collapse from Moderate to Mild, and new critical temperature criteria (≥ 41.0 °C) were added to both Moderate and Severe categories. The revised grading tool was then validated using 422 HRI cases treated during 2023, using univariable logistic regression to evaluate the HRI grades as risk factors for death. The revised tool was deemed to show improved discrimination (area under the receiver operator curve (AUROC): 0.79, 95% CI 0.74–0.84) for predicting a fatal HRI outcome compared to the original tool (AUROC: 0.72, 95% CI 0.66–0.78). This study provides an example of ongoing evaluation and validation that could be applied to other veterinary clinical tools. The revised and validated VetCompass HRI grading tool (2026) should facilitate improved veterinary triage and contextualised care discussions for dogs with HRI.