Affiliation:
1. Virginia Tech Marion duPont Scott Equine Medical Center – Internal Medicine Leesburg Virginia USA
2. Department of Veterinary Clinical Sciences, College of Veterinary Medicine Iowa State University Ames Iowa USA
3. Study Design and Statistical Analysis Lab Virginia Maryland College of Veterinary Medicine Blacksburg Virginia USA
Abstract
AbstractBackgroundDiagnosis 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.ObjectivesTo investigate risk factors associated with the development of colitis and infectious colitis post‐exploratory laparotomy.Study designRetrospective case–control.MethodsMedical 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.ResultsA 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 < 0.001), or plasma lactate 2.0–4.0 mmol/L (OR = 3.0, 95% CI = 1.3–6.7, p < 0.008). Patients diagnosed with colitis had a longer median length of hospitalisation (9 days; range 2–21) compared with patients without colitis (7 days; range 2–25). Patients with colitis had a survival to discharge rate similar to patients without colitis (95% compared to 93%).Main limitationsRisk factors for infectious colitis could not be determined due to variation in testing protocols in this retrospective study and the low number of positive cases.ConclusionsColitis as a postoperative complication does not negatively impact survival to discharge but is associated with longer hospitalisation. Pelvic flexure enterotomy, postoperative leukopenia or leukocytosis, and increased plasma lactate were identified as significant risk factors associated with colitis.