Comparison of the predictive capacity of the Alvarado and AIR scores in the diagnosis of acute appendicitis: A prospective study

Introduction and aim: Acute appendicitis stands out as one of the most frequent surgically-treated diseases. Risk scales for acute appendicitis, such as the Alvarado and AIR scoring systems, show good diagnostic yield. The aim of our study was to compare the predictive capacity between the Alvarado and AIR scores in the diagnosis of acute appendicitis. Methods: A cross-sectional study was conducted on patients that underwent appendectomy due to suspected acute appendicitis, confirmed by histopathology. The predictive capacity of the Alvarado and AIR scores was evaluated through an ROC curve analysis, determining the area under the ROC curve. The STROBE checklist was utilized. Results: A total of 358 patients with clinical suspicion of acute appendicitis were included, 51% of whom were men (183/358). Median patient age was 36 years (IQR: 24-46). The ROC curve of the Alvarado score was 0.767 (95% CI: 0.716-0.818), and with a cutoff point of 0-4, had 78% sensitivity and 84% specificity. The AIR score had a ROC curve of 0.741 (95% CI: 0.691-0.788), and with a 0-4 cutoff point, 87% sensitivity and 56% specificity. There was no statistically significant difference between the 2 scores (p = 0.266). Conclusion: The Alvarado and AIR scores have a similar predictive capacity for acute appendicitis. The low cutoff points of the risk scales are related to greater diagnostic sensitivity of the disease.