Validation of a Scoring System to Distinguish Uncomplicated From Complicated Appendicitis

Background: Studies have shown that uncomplicated appendicitis can be treated conservatively with antibiotics. It is important to select only those patients with uncomplicated appendicitis when considering conservative management. Recently, a scoring system based on clinical evaluation and ultrasound was developed to improve this selection and aid in shared decision making when considering an antibiotics-first strategy. The aim of this study was to externally validate the scoring system. Materials and methods: A retrospective cohort study of all adult patients presenting to the emergency department between January 2014 and January 2017 with suspected acute appendicitis based on clinical evaluation and ultrasound was performed. For every patient, a score was calculated using the previously described scoring system. A final diagnosis, subdivided into complicated appendicitis, uncomplicated appendicitis, complicated alternative disease, and uncomplicated alternative disease, was assigned to every patient based on operative findings. Results: A total of 678 patients with suspected acute appendicitis based on clinical and ultrasonography findings were identified, of whom 175 (25.8%) had complicated appendicitis, 491 (72.4%) had uncomplicated appendicitis, and 12 (1.8%) had an alternative disease. Of the 678 patients, 272 had a score of five points or less, of whom 17 (6.2%) had complicated appendicitis, giving a negative predictive value of 93.8%. Conclusions: With the scoring system based on clinical and ultrasonography features, 93.8% of patients predicted to have uncomplicated appendicitis were correctly identified. The scoring system could help identify patients suitable for conservative management in future studies.