Risk factors associated with development of colitis in horses post‐exploratory laparotomy

Background Diagnosis of colitis has been shown to impact morbidity and mortality in hospitalised horses. There are no studies to date that describe the incidence of infectious colitis after exploratory laparotomy. Objectives To investigate risk factors associated with the development of colitis and infectious colitis post‐exploratory laparotomy. Study design Retrospective case–control. Methods Medical records of equids admitted from 2011 to 2020 were reviewed. The primary outcome was a diagnosis of colitis following exploratory laparotomy. Bivariable associations between colitis and risk factors were assessed using the 2‐sample t‐test and Fisher's exact test. All risk factors were subjected to a backward elimination variable reduction algorithm within a logistic regression framework (p‐value set to 0.05). Odds ratios and 95% confidence intervals were computed for the final model. Results A total of 504 equids were included in the study. Forty‐two patients (8.3%) were diagnosed with postoperative colitis. Five patients were diagnosed with Salmonella spp. and two with Clostridioides difficile. The odds of postoperative colitis were higher among patients that had pelvic flexure enterotomy (OR = 3.7, 95% CI = 1.7–7.9, p = 0.001), postoperative leukopenia or leukocytosis (OR = 21.2, 95% CI = 9.7–46.7, p