Comparison of Rectal and Intraoperative Findings in Horses with Colic

Per rectum examination (PRE) is commonly used in the triage of horses with acute abdominal pain, despite reports of associated risk factors for both horses and personnel, but its diagnostic accuracy is questionable. This multicenter, observational study aimed to evaluate the agreement between PRE findings and surgical findings obtained via exploratory laparotomy in horses with colic. A total of 201 cases from four equine referral hospitals across Europe were included. Rectal findings were categorized as primary (most likely cause of colic) or additional. Agreement with surgical findings was assessed using kappa statistics. The influence of examiner demographic data (age, gender, and qualification status) on diagnostic accuracy was also evaluated. The agreement between primary rectal and primary surgical diagnosis was 57.2% (115/201; kappa coefficient, 0.490; 95% confidence interval, 0.394-0.586). When both primary and additional findings were considered, agreement increased to 71.6% (144/201, kappa coefficient, 0.720; 95% confidence interval, 0.156-0.927; 65.1-77.4%). The highest agreement was seen in cases of gas-distended large colon (90.3%), small intestinal distension (75.8%), and left dorsal displacement of the large colon (66.7%). Detection of small intestine distension in PRE had the highest sensitivity (85.7%) and negative predictive value (92.8%) among the evaluated parameters. Examiner demographics had no significant impact on diagnostic accuracy. PRE is a valuable but imperfect diagnostic tool. Given the dynamic nature of colic and possible changes between examination and surgery, some discrepancies are expected. Other variables, such as horse size or the examiner's hand dominance, were not investigated in this study but may have had an impact on the observed outcomes. Overall, PRE remains a practical, accessible technique that provides clinically useful information regardless of examiner experience.