Risk factors for equine strangulating lipoma colic: An international, case-control study

Obstruction by strangulating lipoma (SLO) is one of the most common causes of small intestinal strangulation in horses and is fatal without surgery. Current knowledge of risk factors for SLO is limited to horse signalment features. To date, other risk factors have not been investigated.

To investigate horse- and management-level risk factors for SLO using a population of healthy horses as controls.

Matched, case-control study.

A prospective, international multicentre study was conducted in the UK and USA between January 2022 and May 2024. Cases were horses with SLO confirmed at exploratory laparotomy at the four participating hospitals. Three controls per case were randomly selected, matched on clinic and time. Conditional logistic regression was used to identify associations between variables and the risk of SLO.

Data from 55 SLO cases (UK, n = 42; USA, n = 13) and 167 matched controls were analysed. In a final multivariable model, increased age (odds ratio [OR]: 1.15; 95% confidence intervals [95% CI]: 1.04-1.28; p = 0.008) and particular breeds (Pony, Welsh Section D/Cob, American Quarter Horse/American Paint Horse/Appaloosa/Arabian) were at increased risk of SLO (OR: 1.53; 95% CI: 1.10-2.15; p = 0.012). SLO was more likely in horses with a prior history of laminitis (OR: 10.94; 95% CI: 2.21-54.13; p = 0.003) or increased stabling in the previous 4 weeks (OR: 6.79; 95% CI: 1.96-23.54; p = 0.003). Management strategies to maintain optimal weight and address equine metabolic syndrome were protective (OR: 0.19, 95% CI: 0.39-0.94; p = 0.041).

Potential for selection and recall bias by horse owners.

This study adds to knowledge of the epidemiology of SLO and has identified new risk factors which may be modifiable. Strategies to prevent endocrine-associated laminitis, including weight management in high-risk groups, should be considered to minimise SLO risk.