Interobserver variation in the endoscopic diagnosis of gastroduodenal ulcer scars: implications for clinical management of NSAIDs users

BACKGROUND: A clinical history of peptic ulcer has been reported to be associated with a high rate of ulcer recurrence in nonsteroidal anti-inflammatory drug (NSAID) users. Therefore, it is a very important issue to precisely know the previous history prior to NSAIDs administration. To clarify the possible difficulty to identify the history, we determined the sensitivity and diagnostic concordance of endoscopy for the identification of ulcer scars indicative of previous clinical history of peptic ulcer diseases. METHODS: The first study enrolled 200 consecutive patients with a clinical history of gastric or duodenal ulcers previously confirmed by esophagogastroduodenoscopy. The sensitivity of endoscopy for identifying scars was determined for these patients. In the second study, the extent of interobserver agreement was determined for 47 endoscopists who identified ulcer scars in endoscopic photographs of 30 sites of previous active gastric ulcers and 30 sites of previous active duodenal ulcers. The kappa coefficient of reliability was calculated to measure the interobserver agreement on the diagnosis of ulcer scars. RESULTS: Out of 190 patients eligible for analysis, 104 (54.7%) were found to have gastric or duodenal ulcer scars on endoscopy; there were no gastric or duodenal ulcer scars seen in the remaining patients (45%). In the second study, the kappa values for endoscopic diagnosis of gastric and duodenal ulcer scars were 0.14 (95% CI 0.13-0.16) and 0.29 (95% CI 0.27-0.32), respectively. The addition of indigo-carmine chromoendoscopy did not provide a statistically significant improvement in diagnostic concordance in patients with gastric ulcer scar since the kappa value for chromoendoscopic diagnosis was 0.15; 95% CI 0.13-0.17 as low as for un-contrasted scars. CONCLUSIONS: The sensitivity and concordance of endoscopic diagnosis of gastric and duodenal ulcer scars are not satisfactory for the use of endoscopy only to identify previous ulcer disease. To avoid the overlooking the previous clinical history of peptic ulcer diseases, the diagnosis of peptic ulcer scar has to be carefully done prior to NSAIDs administration.