COMPARATIVE DIAGNOSTIC ACCURACY OF ALVARADO, AIR, AND RIPASA SCORES IN ADULTS PRESENTING WITH SUSPECTED ACUTE APPENDICITIS: A PROSPECTIVE CROSS-SECTIONAL STUDY

Abstract

Background: Early and accurate diagnosis of acute appendicitis reduces negative outcomes, perforation, and healthcare costs. Clinical scoring systems such as Alvarado, Appendicitis Inflammatory Response (AIR), and RIPASA are widely used, but their performance varies depending on the setting. We wanted to compare their diagnostic accuracy in adults presenting with suspected acute appendicitis at Ayub Teaching Hospital in Abbottabad.

Methods: This prospective cross-sectional study (Jan-Jun 2025) included 250 adults (>18 years) with right lower quadrant pain. The sample size (n=234) was calculated to detect a ΔAUC of 0.05 between scores (80% power, α=0.05), with 250 recruited to account for attrition. Upon admission, Alvarado, AIR, and RIPASA scores were calculated. Histopathology after appendectomy or contrast-enhanced CT/ultrasound, along with clinical follow-up in nonoperative cases, was used to make a definitive diagnosis. We calculated sensitivity, specificity, positive and negative predictive values (PPV and NPV), and AUC using 95% confidence intervals (CI).

Results: Out of 250 patients, 200 (80%) had confirmed appendicitis and 50 (20%) did not (Figure 2). RIPASA demonstrated the highest sensitivity (92%, 95% CI 87-95%) compared to AIR (88%, 83-92%) and Alvarado (85%, 79-89%). AIR had a higher specificity (80%, 66-89%) than RIPASA (78%, 64-88%) or Alvarado (75%, 61-85%) (Table 1). The AUC values were 0.85 (Alvarado), 0.88 (AIR), and 0.90 (RIPASA) (Figure 1). The PPVs ranged from 0.89 (Alvarado) to 0.94 (RIPASA), and the NPVs were from 0.67 to 0.72.

Conclusions: RIPASA had higher overall diagnostic accuracy in our Pakistani cohort, while AIR had better specificity. Adopting RIPASA as a primary screening tool, with AIR for borderline cases, may reduce negative appendectomies and optimize resource use in comparable settings.