Background: Acute appendicitis is still a difficult diagnosis. Scoring systems are designed to aid in the clinical assessment of patients with acute appendicitis. The Alvarado score is the most well known and best performing in validation studies. The purpose of the present study was to externally validate a recently developed appendicitis inflammatory response (AIR) score and compare it to the Alvarado score.
Methods: The present study selected consecutive patients who presented with suspicion of acute appendicitis between 2006 and 2009. Variables necessary to evaluate the scoring systems were registered. The diagnostic performance of the two scores was compared.
Results: The present study included 941 consecutive patients with suspicion of acute appendicitis. There were 410 male patients (44%) and 531 female patients (56%). The area under the receiver operating characteristic curve of the AIR score was 0.96 and significantly better than the area under the curve of 0.82 of the Alvarado score (p < 0.05). The AIR score also outperformed the Alvarado score when analyzing the more difficult patients, including women, children, and the elderly.
Conclusions: This study externally validates the AIR Score for patients with acute appendicitis. The scoring system has a high discriminating power and outperforms the Alvarado score.