Catherine Ennis¹, Jude Bradbury¹, Lucy Leicester², Dan O'Neill¹, Emily Hall¹

¹Royal Veterinary College, London, United Kingdom. ²Vets Now, Dunfermline, United Kingdom

Objectives

Heat related illness (HRI) is a preventable and potentially fatal disease affecting all companion animals, yet previous research has largely focused on dogs. This study aimed to investigate HRI incidence and risk factors in cats.

Methods

HRI cases were identified from anonymised clinical records of cats under Vets Now emergency care (2022-2023) using VetCompass. Patient signalment, history, presentation and outcomes were extracted. Risk factor analysis used multivariable logistic regression.

Results

From 112,527 cats under Vets Now care during 2022-2023, 167 HRI cases were identified; annual incidence risk was 0.15% (95%CI 0.13-0.17%) with 13.17% (95%CI 8.86-19.14%) overall case fatality. At least one case presented in 22 of the 24 study months, 101/167 (60.48%) during heat-health alert periods. Case fatality was significantly lower during (4/101, 3.96%) heat-health alert periods than outside them (18/66, 27.27%, p<0.001). Females (OR 1.60 95%CI 1.16-2.20) and cats <6 months (OR 5.80 95%CI 3.08-11.18) showed increased risk of HRI compared with males and cats 6 months-3 years, respectively. The most common HRI triggers were high environmental temperatures (33.7%), being housed in hot buildings (30.1%), and entrapment in/near hot appliances (18.0%). Pre-existing disease was a noted contributing factor in 42 cases (28.74%), including cardiac (n=8), respiratory (n=8), neurological (n=6) and urogenital (n=6) disorders.

Statement: Impact/ Clinical Significance

Feline HRI is an all-year-round disorder, commonly triggered by indoor and outdoor ambient heat and often overlaid on pre-existing health conditions. Progressively rising global temperatures due to climate change highlight HRI as an emerging disorder of major risk for cats, with peak hazard during human heat-health alerts periods.