Comparative Study on the Diagnostic Validity of the Alvarado Score, Appendicitis Inflammatory Response (AIR), and Adult Appendicitis Score (AAS) in Acute Appendicitis at East Lancashire Hospitals NHS Trust (ELHT)

This retrospective observational study aims to compare the diagnostic accuracy of Alvarado Score, Appendicitis Inflammatory Response (AIR) Score, and Adult Appendicitis Score (AAS) in predicting histologically confirmed acute appendicitis in adult patients presenting to East Lancashire Hospitals NHS Trust (ELHT). The study will include all emergency patients aged 16 years and above, of any gender, admitted between June 2023 and June 2024 with clinical suspicion of acute appendicitis who subsequently underwent appendicectomy via laparoscopic or open approaches. For each patient, the Alvarado, AIR, and AAS scores will be calculated retrospectively using information from presenting symptoms, physical examination findings, and laboratory investigations recorded at the time of admission. These calculated scores will be compared against the final histopathology results, which serve as the gold standard for diagnosis. Diagnostic performance will be assessed using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Sensitivity reflects the proportion of patients with appendicitis correctly identified by the score, while specificity measures the ability to correctly exclude those without the condition. PPV indicates the likelihood that a positive score truly represents acute appendicitis, whereas NPV represents the likelihood that a negative score accurately rules it out. Accurate and timely pre-operative diagnosis of acute appendicitis is essential to minimise the incidence of negative appendicectomies while avoiding unnecessary diagnostic investigations. This study also aims to determine the most effective scoring system for risk stratification in the local adult population, considering the demographic diversity, and to provide recommendations for the standardisation of appendicitis risk assessment tools in emergency surgical practice within the trust.