Indicators of ‘critical’ outcomes in 941 horses seen ‘out-of-hours’ for colic

Background: This study aimed to describe the presentation and outcomes of horses with signs of colic (abdominal pain) seen ‘out-of-hours’ in equine practice. Methods: This was a retrospective study of horses seen ‘out-of-hours’ with colic by two equine veterinary practices between 2011-2013. Case outcomes were categorised as ‘critical’ or ‘not critical’. A critical outcome was defined as requiring medical or surgical hospital treatment, or resulting in euthanasia or death. A non-critical outcome was defined as resolving with simple medical treatment. A hierarchical generalised linear model was used to identify ‘red flag’ parameters (aspects of signalment, history and presenting clinical signs) associated with critical outcomes.Results: Data were retrieved from 941 cases that presented with colic; 23.9% (n=225/941) were critical. Variables significantly associated with the likelihood of a critical outcome in the final multivariable mode were: increased heart rate (p [less than] 0.001), age of the horse (p=0.013) and abnormal mucous membrane colour (p [less than] 0.001). Overall 18% of cases (n=168/941) were euthanased.Conclusions: This study highlights the mortality associated with colic. The ‘red flag’ parameters identified should be considered an essential component of the primary assessment of horses with colic