Moderate quality (B) was defined as a recommendation from a well-designed controlled or uncontrolled non-randomized study that may not have been reproducible by follow-up studies. Low quality (C) was defined Barasertib as a recommendation where the estimated value of the effect was uncertain. C-level information included non-randomized

studies, case reports, expert opinions, guidelines, experts’ consensus, and recommendations based on clinical experience of the guideline developers.[17] Grade of recommendation was either strong (1) or weak (2). A strong recommendation was defined as a recommendation that was significantly more effective, could be applied to most patients in most circumstances, and would be reproducible in future studies. A weak recommendation was defined as a recommendation with inconsistent results that might not be reproducible in future studies. A panel of experts was selected Trichostatin A from members of the Guideline Steering Committee, current and former board members, and members of the Korean College of Helicobacter

and Upper Gastrointestinal Research, the Korean Society of Gastroenterology, the Korean Society of Pathologists, and the Korean Society of Clinical Microbiology. The Delphi technique was used to help these experts reach a consensus concerning final recommendations. The first draft consisted of 21 recommendations: 12 concerning the indication of diagnosis and treatment of H. pylori, four regarding diagnosis, and five regarding treatment of H. pylori infection. The recommendations and related documentation were emailed to the panel 1 week before the vote so that the panel could review the information in detail. A total of 31 doctors participated in the first round of Delphi consensus, including 28 gastroenterologists and three pathologists. After members of the

Development Committee explained the basis of the literature review and announced the level of evidence and grade of recommendation, panel members voted for each recommendation using a keypad that ensured anonymous voting. Degree of agreement on the draft recommendations was determined using a 5-point Likert scale as follows: 1, completely agree; 2, mostly agree; 3, partially agree; 4, mostly disagree; 5, completely disagree; ifenprodil 6, not sure. If at least two-thirds of the panel members completely or mostly agreed with a recommendation, it was considered an agreement on the draft. Of the 21 recommendations, 14 were selected, five were dismissed, and two were rejected. The Guideline Development Committee adjusted seven recommendations that were dismissed in the first Delphi meeting and conducted the second Delphi meeting via email. The second meeting focused on the level of agreement for the newly revised recommendations. There were 27 respondents.