Agreement among multiple observers on endoscopic diagnosis of esophageal varices before bleeding

The interobserver variation in diagnosis and grading of esophageal varices may be ascribed by characteristics of the observers as well as to the patients. Assessment of this variation therefore requires the contributions of multiple observers and patients. Twenty-eight patients with cirrhosis without previous bleeding or known presence of varices were subjected to upper gastrointestinal endoscopy. Each endoscopy was videotaped and shown to 22 endoscopists. The varices were graded on a scale of 0 to 3 according to size. Each endoscopist diagnosed varices in 8 to 20 patients (mean = 15.9). Overall agreement on the presence (grades 1 to 3) or absence (grade 0) of varices was 70%. The average kappa value was 0.38 (standard deviation = 0.16). Discrimination between varices graded 0 to 1 and varices graded 2 to 3 gave a higher kappa value (p less than 0.01) of 0.52 (standard deviation = 0.17). There was a large variation in kappa values (range = -0.025 to 0.975). No significant correlation was observed between kappa values for the two dichotomies (range = 0.16). The kappa values were not related to the experience of the endoscopist. Considerable variation in the agreement on diagnosis and grading of esophageal varices was found. These results must be taken into account in the assessment of trials of prophylaxis of first-time variceal bleeding.