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 and 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 per cent (n=225/941) were critical. Variables significantly associated with the likelihood of a critical outcome in the final multivariable model were increased heart rate (P<0.001), age of the horse (P=0.013) and abnormal mucous membrane colour (P<0.001). Overall 18 per cent (n=168/941) of cases 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.