Validation of the appendicitis inflammatory response score in a provincial population

Background: The appendicitis inflammatory response (AIR) score is a high performing, and easy to use clinical prediction tool for the evaluation of appendicitis, but its efficacy has not been studied in the provincial setting. This retrospective, single centre study aims to validate the AIR score, estimate the effect AIR score-based risk stratification would have on the negative appendicectomy rate and compare it against other well-known clinical prediction tools for appendicitis. Methods: 425 patients treated with appendicectomy or laparoscopy between 1 st Jan 2015 and Dec 31 st 2017 were retrospectively provided with an AIR score. This score was compared against the final macroscopic and histological results to determine its accuracy in the local population. Results: The AIR score did not perform as well as in other published series, with an area under the receiver operating characteristic curve (AUC) of 0.836. The AIR score performed favourably in comparison to the Alvarado score (0.761), APPEND score (0.747) and adult appendicitis score (AAS) (0.828). Conclusions: This study showed that the AIR score has a high accuracy, and validates its use in a provincial setting. AIR score-based management of appendicitis would be expected to reduce non-therapeutic explorations by a minimum of 50%.