Effect of pronase premedication on narrow-band imaging endoscopy in patients with precancerous conditions of stomach.

BACKGROUND: Narrow-band imaging (NBI) endoscopy improves the detection of intestinal metaplasia. However, strategies to improve the visibility and diagnostic performance of NBI should be sought, as endoscopic views are often obscured by the presence of mucus. AIM: To compare the visibility and diagnostic performance of NBI endoscopy according to pronase premedication in patients with precancerous conditions of the stomach. METHODS: Consecutive outpatients with a previous diagnosis of precancerous condition of the stomach were invited to undergo a surveillance NBI endoscopy between June and December 2012. Enrolled subjects were randomly assigned to pronase or control groups before NBI endoscopy. The visibility score and diagnostic performance of NBI endoscopy were compared between the two groups. RESULTS: Patients' endoscopic and histopathological characteristics were similar between the two groups. Visibility score in the proximal part of the stomach and satisfaction score of the endoscopist were significantly higher in the pronase group than in the control group (p = 0.014 and p = 0.034, respectively). The diagnostic performance of NBI endoscopy to detect intestinal metaplasia was not different in either group (both p > 0.1). However, the negative predictive value of NBI endoscopy was much improved over that of white light endoscopy only in the pronase group (p = 0.013). CONCLUSION: Pronase premedication increased the visibility of the proximal part of the stomach and the satisfaction score during NBI endoscopy. Furthermore, negative predictive value of NBI endoscopy was much improved compared with that of white light endoscopy after pronase premedication.