Modelling long-term survival of horses following surgery for large intestinal disease

REASONS FOR PERFORMING STUDY: Large intestinal diseases are an important cause of equine colic that require surgical management, but there is little published information about long-term survival of such cases. OBJECTIVES: To identify variables associated with post operative mortality and to develop a model for post operative survival following surgery for large intestinal disease. METHODS: Clinical data and long-term follow-up information from 275 horses undergoing surgery for large intestinal disease were used. A multivariable, Cox proportional hazards model for post operative death was developed and the fit of the model evaluated. RESULTS: The continuous variables age, heart rate and packed cell volume (PCV) were associated positively with the risk of post operative death, as were the categorical variables resection (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.2-5.1) and relaparotomy (OR 3.5, 95% CI 1.4-8.4). CONCLUSIONS: In the population studied, the probability of post operative survival following surgery for large intestinal disease was associated with the cardiovascular parameters heart rate and PCV on admission, age of the horse and whether it underwent resection or relaparotomy. POTENTIAL RELEVANCE: The prognosis for post operative survival for horses with large intestinal disease may be improved by early surgery, prior to the development of cardiovascular compromise. Surgeons should be aware that increasing age, resection of large colon and relaparotomy are all associated with a worsening prognosis for survival.