Background: The accuracy of the clinical diagnosis of acute appendicitis in patients more than 50 years old was studied in connection with the Research Committee of the World Organization of Gastroenterology (OMGE) survey of acute abdominal pain. Criteria for inclusion and the diagnostic criteria in this prospective study were those set out by the OMGE Research Committee.
Methods: The clinical findings in each patient were recorded in detail, using a predefined structured data collection sheet, and the collected data were compared with the final diagnosis of the patients. Twenty-three preoperative clinical history variables, 14 clinical signs, and 3 tests were evaluated in a single variable and multivariate analysis.
Results: In multivariate logistic regression analysis the most significant predictors of acute appendicitis in patients more than 50 years old were tenderness (relative risk (RR) = 39.4), rigidity (RR = 18.8), and pain at diagnosis (RR = 11.0). The sensitivity of the preoperative clinical decision is detecting acute appendicitis in the aged was 0.87, with a specificity of 0.92, an efficiency of 0.91 and a usefulness index (UI) of 0.69. The computer-aided diagnostic score (DS) reached a sensitivity of 0.92 in detecting acute appendicitis, with a specificity of 0.90 and an efficiency of 0.90. When the patients with a DS value between -0.47 and 0.07 were considered nondefined (n = 43, follow-up required before the decision to operate), the efficiency of the computer-aided diagnosis in detecting acute appendicitis in the aged improved to 0.97. In patients more than 50 years old whose body temperature was available (n = 374), tenderness, rigidity, location of pain at diagnosis, and body temperature predicted significantly acute appendicitis. At a cut-off level of -1.49 the diagnostic score reached a sensitivity of 0.94 in detecting acute appendicitis, with a specificity of 0.91, an efficiency of 0.92 and a UI of 0.80. When the patients with a DS value between -1.49 and 0.46 were considered nondefined (n = 43, follow-up required before the decision to operate), the sensitivity of the computer-aided diagnosis in detecting acute appendicitis in the aged was 0.92, with a specificity of 0.99 and an efficiency of 0.98, and the UI improved to 0.84.
Conclusion: Acute abdominal pain at the right lower quadrant, with tenderness, rigidity, and increased body temperature (> or = 37.1 degrees C), is indicative of acute appendicitis in patients more than 50 years old. The diagnostic scoring system did perform well, increasing the sensitivity, specificity, efficiency, and usefulness index of the diagnosis of acute appendicitis in the aged.