Diagnostic performance of RIPASA versus modified Alvarado score in acute appendicitis: a prospective diagnostic accuracy study from a tertiary centre in India

PURPOSE: Acute appendicitis is a common surgical emergency. Clinical scores assist risk stratification where routine advanced imaging is impractical. The Alvarado score's performance in Asian populations is debated. The Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) score was developed for Asian settings. This study prospectively compared RIPASA and the Modified Alvarado Score (MAS) against histopathological examination (HPE) in an Indian tertiary centre. METHODS: Prospective diagnostic accuracy study of 62 patients undergoing appendicectomy for suspected acute appendicitis at S.M.S. Medical College, Jaipur (January-December 2024). Pre-operative demographics, symptoms, signs and laboratory parameters were recorded; RIPASA (cut-off ≥ 7.5) and MAS (cut-off ≥ 7) were calculated. HPE was the reference standard. Outcomes were sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the receiver operating characteristic curve (AUC) with standard error (SE) and 95% confidence interval (CI). AUCs were compared using DeLong's test, and paired sensitivities and specificities using McNemar's test. RESULTS: Participants were predominantly males (71.0%); mean age 30.66 years. HPE confirmed appendicitis in 56/62 (90.3%); negative appendicectomy rate 9.7%. RIPASA ≥ 7.5: sensitivity 94.6%, specificity 66.7%, PPV 96.4%, NPV 57.1%, AUC 0.921 (SE 0.052; 95% CI 0.820-1.000; p = 0.001). MAS ≥ 7: sensitivity 71.4%, specificity 83.3%, PPV 97.6%, NPV 23.8%, AUC 0.821 (SE 0.083; 95% CI 0.659-0.984; p = 0.010). DeLong's test showed superior discrimination for RIPASA (p = 0.030). McNemar's test demonstrated higher sensitivity for RIPASA (p = 0.0009), with no significant difference in specificity (p = 1.000). CONCLUSION: RIPASA demonstrated higher sensitivity and better diagnostic discrimination than MAS in this tertiary surgical cohort, while MAS showed higher specificity. RIPASA may help reduce missed diagnoses in similar high-prevalence emergency settings, although further validation in broader patient populations is warranted.