Diagnostic Accuracy of the Modified Alvarado and RIPASA Scoring Systems in Acute Appendicitis: A Retrospective Cohort Study

Background : Acute appendicitis (AA) is the leading cause of acute abdomen requiring emergency surgery worldwide. Clinical scoring systems such as the modified Alvarado and RIPASA scores are widely used to improve diagnostic accuracy. Evidence comparing these measurement scales against histopathological findings in our population remains limited, highlighting the need for local validation studies. Objective : To evaluate the diagnostic performance of the Alvarado and RIPASA scores against histopathological findings in adult patients undergoing laparoscopic appendectomy at a quaternary referral center. Methods : A retrospective cohort study was conducted including consecutive patients ≥18 years who underwent laparoscopic appendectomy for suspected AA between January 2021 and June 2022. Alvarado and RIPASA scores were calculated. Associations between scores and histopathological severity were assessed. Statistical significance was set at a two-sided p < 0.05. Results : A total of 501 patients were included; 490 (97.8%) had histopathologically confirmed appendicitis, and complicated appendicitis occurred in 38.5% (n = 193) of cases. At prespecified cutoffs, both scores demonstrated high sensitivity (>97%); however, specificity was markedly low (<4%), and overall AUC values were close to chance (Alvarado: 0.566; RIPASA: 0.496), reflecting severe spectrum bias due to the surgical selection of this cohort. Nonetheless, both the Alvarado (OR 1.25, 95% CI 1.12–1.40; p < 0.001) and RIPASA (OR 1.12, 95% CI 1.03–1.21; p = 0.008) scores were statistically associated with intraoperative disease severity. Similarly, an NLR exceeding 9.95 was associated with complicated appendicitis (p < 0.01). These odds ratios reflect epidemiological associations and should not be interpreted as measures of predictive or diagnostic performance Conclusion : In this surgically managed cohort, both scoring systems demonstrated high sensitivity but modest overall discriminatory metrics, a pattern primarily attributed to spectrum bias. Nevertheless, their statistically significant association with intraoperative severity and the observed association with NLR suggest potential descriptive value in characterizing disease complexity within this surgically selected population. These findings should not be interpreted as evidence of clinical predictive capacity or standalone diagnostic utility.