Performance and diagnostic accuracy of scoring systems in adult patients with suspected appendicitis

BACKGROUND: This study aims to determine the most accurate appendicitis scoring system and optimal cut-off points for each scoring system.

METHODS: This single-centred prospective cohort study was conducted from January-to-June 2021, involving all patients admitted on suspicion of appendicitis. All patients were scored according to the Alvarado score, Appendicitis Inflammatory Response (AIR) score, Raja Isteri Pengiran Anak Saleha (RIPASA) score and Adult Appendicitis score (AAS). The final diagnosis for each patient was recorded. Sensitivity and specificity were calculated for each system. Receiver operating characteristic (ROC) curve was constructed for each scoring system, and the area under the curve (AUC) was calculated. Optimal cut-off scores were calculated using Youden's Index.

RESULTS: A total of 245 patients were recruited with 198 (80.8%) patients underwent surgery. RIPASA score had higher sensitivity and specificity than other scoring systems without being statistically significant (sensitivity 72.7%, specificity 62.3%, optimal score 8.5, AUC 0.724), followed by the AAS (sensitivity 60.2%, specificity 75.4%, optimal score 14, AUC 0.719), AIR score (sensitivity 76.7%, specificity 52.2%, optimal score 5, AUC 0.688) and Alvarado score (sensitivity 69.9%, specificity 62.3%, optimal score 5, AUC 0.681). Multiple logistic regression revealed anorexia (p-value 0.018), right iliac fossa tenderness (p-value 0.005) and guarding (p-value 0.047) as significant clinical factors independently associated with appendicitis.

CONCLUSION: Appendicitis scoring systems have shown moderate sensitivity and specificity in our population. The RIPASA scoring system has shown to be the most sensitive, specific and easy-to-use scoring system in the Malaysian population whereas the AAS is most accurate in excluding low-risk patients.