Development and validation of a risk score predicting acute uncomplicated appendicitis

Abstract

Introduction-Aim: Acute appendicitis (AA) is the most frequent emergency among non-traumatic abdominal emergencies. The aim of this study was to identify independent predictive factors for acute uncomplicated appendicitis (UCAA) and to define a predictive score. METHODS: A retrospective study was conducted in the surgical department B of Charles Nicolle's Hospital of Tunis from January 1, 2013 to December 31, 2014. All consecutive patients operated on for AA were included. The diagnosis was confirmed by operative findings, macroscopic and histological examination of the removed appendix. Complicated acute appendicitis (CAA) was defined by the intraoperative findings of an appendicular abscess or generalized peritonitis. The Score was developed based on a logistic regression to identify the independent and predictive factors among the pre, intra and postoperative variables. RESULTS: This study (335 patients) allowed us to identify the independent factors predictive of CAA, i.e. the duration of pain evolution in the right lower quadrant (OR = 1,444; 95% IC = [1,204 - 1.725]; p < 10-3), guarding of the right lower quadrant (OR = 2.234; 95% CI = [1.051 - 4.749]; p = 0.037) and CRP > 86,8 mg/l (OR = 1.012; 95% CI = [1.008 - 1.016]; p < 10-3). The area under the curve of the score was 0.884 with a 95% CI [0.837 - 0.980]; p < 0.001. This score was validated on a sample of 236 patients culled between January 1, 2015 to May 16, 2016. CONCLUSION: Patients admitted for AA with a duration of symptom progression less than 2 days, without right lower quadrant guarding on clinical examination and with a CRP level < 86.8 mg/l have a risk of 96% (95%CI = [93% - 99%]) of having a UCAA.