Comparative Diagnostic Accuracy of RIPASA and Modified Alvarado Scores in Acute Appendicitis: Insights from an Indian Tertiary Centre

Highlight

• The RIPASA score demonstrated higher sensitivity (94.6%) and better overall diagnostic discrimination (AUC 0.921) compared to the Modified Alvarado Score (MAS) in an Indian tertiary care setting.

• Modified Alvarado Score showed higher specificity (83.3%) than RIPASA (66.7%), implying fewer false positives but more missed cases.

• The study involved 62 patients undergoing appendectomy, with histopathological examination (HPE) as the diagnostic gold standard.

• RIPASA’s improved diagnostic performance suggests its utility in high-prevalence Asian populations where advanced imaging is not routinely accessible.

Study Background

Acute appendicitis remains one of the most common causes of acute abdomen and an important surgical emergency worldwide, requiring prompt diagnosis and intervention. Despite advances in imaging, clinical scoring systems are vital in resource-limited settings to aid risk stratification and decision-making. The Alvarado score, originally developed in Western populations, has had variable performance in Asian cohorts, possibly due to demographic and clinical presentation differences. In response, the Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) score was developed to better suit Asian patients, incorporating additional variables like age and gender to enhance sensitivity.

This study conducted at S.M.S. Medical College, Jaipur, India, prospectively compares the diagnostic accuracy of RIPASA and the Modified Alvarado Score (MAS) with histopathological examination (HPE) after appendectomy as the gold standard. The aim is to clarify which scoring system better identifies true cases of appendicitis in an Indian tertiary surgical cohort and to assess their relative diagnostic performance metrics.

Study Design

The investigators conducted a prospective diagnostic accuracy study from January to December 2024, enrolling 62 consecutive patients presenting with clinical suspicion of acute appendicitis who underwent appendectomy. Data collected included demographic details, clinical signs and symptoms, and laboratory parameters necessary to compute both scores. The RIPASA score cutoff was set at ≥7.5 and MAS cutoff at ≥7, based on prior validation studies.

Histopathological examination of the resected appendix served as the reference standard to confirm or exclude appendicitis. The primary outcome measures were sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC) for each scoring system. RPISA and MAS performances were statistically compared using DeLong’s test for AUC and McNemar’s test for paired sensitivity and specificity differences.

Key Findings

The study cohort comprised 71% males with a mean age of 30.66 years. Of the 62 patients undergoing appendectomy, histopathology confirmed appendicitis in 56 cases (90.3%), yielding a negative appendectomy rate of 9.7%.

For the RIPASA score at cutoff ≥7.5, sensitivity was 94.6%, substantially higher than MAS sensitivity of 71.4% at cutoff ≥7. Specificities were 66.7% and 83.3% for RIPASA and MAS respectively. The PPVs were high in both scores (96.4% for RIPASA and 97.6% for MAS), though NPVs were relatively low, especially for MAS (23.8%) compared to RIPASA (57.1%).

The AUC, reflecting overall diagnostic accuracy, was 0.921 for RIPASA versus 0.821 for MAS, with a statistically significant difference favoring RIPASA (p=0.030). McNemar’s test indicated the higher sensitivity of RIPASA was statistically significant (p=0.0009), while no difference was identified in specificity (p=1.000).

Expert Commentary

The findings underscore the superior sensitivity and diagnostic discrimination of the RIPASA score in the studied Indian population, likely reflecting its design emphasis on features pertinent to Asian patients. Higher sensitivity is crucial in acute appendicitis to minimize missed diagnoses that could lead to perforation and increased morbidity.

The MAS’s higher specificity implies fewer unnecessary surgeries, but at the cost of lower sensitivity, which could be problematic in emergency settings where the priority is often to rule out serious pathology. The RIPASA score’s balanced performance may thus offer practical advantages for early identification, especially where imaging resources are scarce.

Limitations include the relatively small sample size and single-center design which may affect generalizability. Furthermore, the high prevalence of appendicitis in this cohort (90.3%) may inflate certain predictive values. Future multicenter validation studies in diverse Indian and broader Asian populations can help establish robust clinical guidelines.

Conclusion

This prospective study from a tertiary Indian centre confirms that the RIPASA score outperforms the Modified Alvarado Score in sensitivity and overall diagnostic accuracy for acute appendicitis. While MAS demonstrates higher specificity, RIPASA’s superior sensitivity and discriminatory capability may be more valuable in emergency surgical settings with high appendicitis prevalence and limited imaging. Integration of RIPASA into clinical practice protocols could reduce missed appendicitis cases and improve patient outcomes. However, broader validation and contextual adaptation remain necessary before widespread adoption.

Funding and Trial Registration

No specific funding was reported for this study. Trial registration details were not indicated in the source publication.

References

Singh H, Yadav RK, Khan F, Agarwal G, Gupta S, Garg V. Diagnostic performance of RIPASA versus modified Alvarado score in acute appendicitis: a prospective diagnostic accuracy study from a tertiary centre in India. BMC Surg. 2026 Jul 3. doi: 10.1186/s12893-026-04020-w. Epub ahead of print. PMID: 42399848.