Background and Aim Guidelines for selecting the eradication regimen for Helicobacter pylori reinfection remain unclear. This study aimed to evaluate the eradication rate of H. pylori reinfection in patients with a previous infection successfully eradicated with index triple therapy. Methods This was a single‐center, retrospective case–control study. A total of 10 468 H. pylori‐infected patients treated with proton‐pump inhibitor‐based triple eradication therapy at a tertiary medical institution between 2005 and 2016 were enrolled. We reviewed the medical records of the enrolled patients and compared the treatment outcomes in those with H. pylori reinfection after a successful eradication. Results Helicobacter pylori infection was successfully eradicated with the index triple therapy in 7770 patients (74.2%). Among 3567 patients followed up for > 1 year, H. pylori reinfection occurred in 420 (11.8%; 3.06% per person‐year) during a median follow‐up of 39.1 months (interquartile range, 23.5–58.7 months). Of these patients, 164 received eradication therapy for reinfection (triple therapy in 102 and quadruple therapy in 62) and had follow‐up data. Triple therapy showed an eradication rate of 78.4% for H. pylori reinfection, which was not significantly different from that of the index triple therapy (P = 0.394). Quadruple therapy for reinfection exhibited a better eradication rate (87.1%) than triple therapy but without statistical significance (P = 0.237). Conclusions Retreatment with triple therapy for H. pylori reinfection after successful eradication of prior infection showed comparable outcomes to the index triple therapy. Bismuth‐containing quadruple therapy for reinfection tended to have a better eradication rate than did triple therapy.

Background/Aims: Autoimmune pancreatitis (AIP) often occurs with obstructive jaundice in old age in cases of weight loss, mimicking pancreatobiliary cancer. This study aimed to determine the sensitivity and specificity serum IgG, IgG4 and CEA, CA 19-9 levels for the diagnosis of AIP and their ability to distinguish AIP from pancreatobiliary cancer. Methods: The level of serums IgG, IgG4 and CEA, CA 19-9 were measured in 413 patients including 125 with AIP, 201 with pancreatic cancer, and 87 with cholangiocarcinoma. Results: Among AIP patients, 43.2% (54/125) showed elevated IgG levels (≥1,800 mg/dL) and 52% (65/125) showed elevated IgG4 levels (≥135 mg/dL). Sensitivity and specificity of elevated serum IgG for diagnosis AIP were 43% and 88% respectively, and 52% and 97%, respectively for elevated serum IgG4. When the cut-off value of serum IgG4 was raised to 270 mg/dL (twice the upper limit of normal), the specificity improved to 100%. About 25% of the AIP patients showed an increased level of CA 19-9 at ＞37 U/mL and about 12.2% of them showed an increased level of CA 19-9 at ＞100 U/mL. On the contrary, only 1.8% of the AIP patients showed an increased level of CEA at ＞6.0 ng/mL. Conclusions: To avoid unnecessary surgeries resulting from a misdiagnosed pancreatobiliary cancer as opposed to AIP, it is necessary to consider both serum immunoglobulin and tumor marker. In particular, because high level of IgG4 (≥270 mg/dL) and CA19-9 (＞100 U/mL) are relatively rare in pancreatobiliary cancer and AIP, respectively, they will be helpful in differential diagnosis. (Korean J Gastroenterol 2013;61:327-332)