Non-Diagnostic Sonography May Reduce Negative Appendicectomy Rate In Women When Combined With Abbreviated Alvarado Score

Background: The diagnosis of acute appendicitis (AA) remains a clinical one, with selective use of adjunct imaging. Patients with equivocal clinical presentation often undergo a diagnostic laparoscopy. To help reduce negative appendicectomy rates in women, we aimed to develop a simple scoring system based on the Alvarado score (AS) and ultrasound scan (US), as a diagnostic aid for AA in females.Methods: All patients who underwent appendicectomy for AA at The Alfred Hospital Melbourne between 1 July 2012 and 30 June 2017 were included for this case-control study. Logistic regression was used to identify pre-operative parameters predictive of AA. Histopathological identification of AA was interpreted as the gold standard. Statistical analysis was performed using IBM SPSS Statistics V26.Results: A total of 1194 patients were included, with 26% negative appendicectomy rate in women. Of the 8 parameters in the AS, logistic regression identified migratory pain, leukocytosis and leukocyte left shift as most significant predictors for AA. These three parameters were used in a 3-point test which carried a sensitivity of 92.1% and specificity of 28.7%. In women, a negative or non-diagnostic US improved the negative predictive value of the 3-point test from 57% to 82%.Conclusion: The 3-point abbreviated AS in combination with US may be clinically useful in women to exclude appendicitis without diagnostic laparoscopy. Further large-scale prospective studies are required to validate the utility across different subgroups.