EGS P40 Validating the Alvarado Score as a Diagnostic Tool for Acute Appendicitis in a UK District General Hospital

Abstract

Abstract Background Acute appendicitis (AA) remains one of the most common causes of an acute abdomen, requiring surgery. However, ruling out AA remains clinically challenging and has both economic and medico-legal implications for hospital trusts. The 2019 World Society of Emergency Surgery (WSES) guidelines endorsed the use of the Alvarado score to limit diagnostic uncertainty. Particularly, a score below 5 was deemed sufficiently sensitive to exclude AA without imaging. This audit aimed to retrospectively assess the use of the Alvarado score to exclude AA in patients referred with suggestive symptoms to the on-call general surgery team at a UK District General Hospital. Methods All patients referred to the on-call general surgery team between 2nd January 2023 and 5th February 2023 with right-lower-quadrant (RLQ) abdominal pain or an incidental diagnosis of AA were included. Patient demographics, clinical data, and an admission Alvarado score were retrospectively collected. An average admission Alvarado score was calculated for patients with confirmed AA and those without. As recommended in the WSES guidelines, a cut-off score of < 5 was employed. The sensitivity and specificity were then calculated in order to validate the Alvarado score’s use as a diagnostic tool in patients with suspected AA. Results Of the 63 patients referred with RLQ abdominal pain, one self-discharged and 11 (17.7%) had confirmed AA on imaging or histology (Figure 1). The average Alvarado score was 4.9 (95% CI 4.2 – 5.5). In patients with confirmed AA, the average score was 7.5, statistically significantly ≥ 5 (p-value <0.01). Patients without AA averaged a score of 4.3, statistically significantly < 5 (p-value = 0.013). The sensitivity and specificity were 91% (95% CI 58.7% – 99.8%) and 47% (95% CI 32.9% – 61.5%), respectively. The positive and negative predictive values were 27% (95% CI 13.8% – 44.1%) and 96% (95% CI 79.7% – 99.9%), respectively. Conclusions This retrospective audit highlighted that the Alvarado score could have been safely used to exclude AA in patients with scores below 5, avoiding the need for further investigations and treatment. A second, prospective study will aim to further validate and implement the routine use of the Alvarado score in the department to improve the diagnostic work-up of patients with suspected AA. The economic impact of its use should also be investigated with a health economics multi-centric study.