The Diagnostic Validity of the Urea Breath Test

1-1 Screening (visit 1, From -6 to -8 weeks) and H. pylori eradication

• To accept the agreement, confirm inclusion/exclusion criteria, and evaluate the baseline characteristics of patients
• H. pylori eradication

• First eradication: PPI-based triple therapy (standard dose of PPI b.i.d., clarithromycin 500 mg b.i.d., and amoxicillin 1 g b.i.d. for 1 week), and sequential therapy (initial 5-day therapy with a combination of PPI b.i.d and amoxicillin 1g b.i.d, followed by 5 days of PPI b.i.d., clarithromycin 500mg b.i.d., and metronidazole 500mg t.i.d)
• Rescue therapy: bismuth-containing quadruple therapy [PPI b.i.d., tripotassium dicitrate bismuthate 300 mg q.i.d. (three tablets at 30 min before meals and one tablet at 2 hours after dinner), metronidazole 500 mg t.i.d., and tetracycline 500 mg q.i.d.] for 1-2 weeks, or moxifloxacin-containing triple therapy (moxifloxacin 400 mg q.d., amoxicillin 1g b.i.d., and PPI b.i.d.) for 1-2 weeks.

1-2 Baseline (visit 2, 0 week): urea breath test

• Reconfirm inclusion and exclusion criteria
• Randomization for UBT test (citric acid group vs control group)
• In citric acid group: taking 4 g of citric acid solving in 200 ml of water 10 minutes before UBT.
• Perform UBT in both group

1-3) Endoscopic surveillance (visit 3, 6 or later months)

• Endoscopic surveillance for final H. pylori status after UBT

• Histology, CLOtest or H. pylori culture
• Statical analysis for diagnostic accuracy of the UBT between citric acid group and controlled group: sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, and false negative rate.

• Selecting 40 patients who showed UBT result between 2.5 to 4.0 in controlled group, the investigators are planning to reperform 13C-UBT after giving citric acid as test meal.

And then, the investigators compare the change of UBT result before and after ingestion citric acid as test meal.

Inclusion criteria

• Male and female Korean adult (Aged over 18 years)
• The Patients who diagnosed H. pylori infection and received H. pylori eradication therapy

Exclusion criteria

• Age under 18 years
• Patients who took any drug which could affect the study results such as proton pump inhibitor, H2 blocker, mucosal protective agents and antibiotics
• Advanced gastric cancer or other malignancy
• Abnormal liver function test or liver cirrhosis
• Abnormal renal function or chronic kidney disease
• Other severe concurrent disease