Receiver operating characteristic analysis of the diagnostic performance of a computed tomographic examination and the Alvarado score for diagnosing acute appendicitis: emphasis on age and sex of the patients.

OBJECTIVE: To compare the diagnostic performance of computed tomography (CT) and the Alvarado score and to determine whether patient age and sex influence the use of CT and the Alvarado score for diagnosing acute appendicitis.
MATERIALS AND METHODS: We retrospectively reviewed the CT scans and medical records of 372 patients who presented with right lower quadrant pain and underwent CT to rule out acute appendicitis.The population was classified by age and sex to determine its influence on the use of the Alvarado score and CT. Receiver operating characteristic analysis was used to calculate and compare the diagnostic performance of both modalities.
RESULTS: The overall area under the receiver operating characteristic curves for CT and the Alvarado score was 0.965 (highly accurate) and 0.732 (moderately accurate), respectively. There was little effect of patient age and sex on diagnostic performance of CT. However, the diagnostic performance of the Alvarado score was variable according to the patient age and sex (lowest in older women). Furthermore, the overall sensitivity of the Alvarado score was too low (72.8%) for determining immediate surgical intervention.
CONCLUSION: Clinical assessment using the Alvarado score should be supplemented with CT examination for accurate diagnosis of acute appendicitis in all patients who are suspected of acute appendicitis.