Comparison of the diagnostic values of MASS, RIPASA, AIR, and AAS scores in adult patients presenting to the emergency department with suspected appendicitis

Abstract Objective Acute appendicitis (AA) is one of the most common causes of acute abdomen. Its diagnosis requires the combined evaluation of clinical, laboratory, and radiological findings. This study aimed to compare the effectiveness of the MASS (Modified Alvarado Score), RIPASA (Raja Isteri Pengiran Anak Saleha Appendicitis) Score, AIR (Appendicitis Inflammatory Response) Score, and AAS (Adult Appendicitis Score) in the diagnosis of AA. Materials and methods This single-center, prospective, observational cohort study was conducted in the emergency department (ED) of a tertiary hospital. Patients aged 18 years and older with suspected AA who presented to the ED were included in the study. Patients’ demographic characteristics, clinical findings, laboratory, and imaging results were recorded. MASS, RIPASA, AIR, and AAS scores were calculated. Patients were divided into two groups based on their ED management: surgical and conservative. In the surgical group, intraoperative findings and/or histopathological results were taken as the gold standard for the final diagnosis. In the conservative group, the presence of appendicitis in patients with alternative or indefinite diagnoses was re-evaluated after a 4-week follow-up period. Patients were divided into two groups based on their final diagnosis: ‘AA’ and ‘non-AA’, Results A total of 238 patients were included, of whom 110 (46.2%) were diagnosed with AA. All four scoring systems demonstrated statistically significant discrimination between AA and non-AA groups. The AUC values were 0.736 for MASS, 0.719 for RIPASA, 0.786 for AIR, and 0.822 for AAS. At the optimal cut-off values determined by the Youden index, AAS showed the highest sensitivity (81.8%), while AIR demonstrated the highest specificity (77.3%). Pairwise DeLong comparisons indicated that AAS had significantly higher AUC values than MASS and RIPASA. The negative appendectomy rate in this cohort was 12.1%. Conclusion These findings, while specific to this cohort, suggest that AAS may function as a supportive tool in AA risk stratification; however, external validation is needed in larger, multicenter populations.