ROLE OF SEROCONVERSION IN CONFIRMING CURE OF HELICOBACTER-PYLORI INFECTION

Context.-The role of serologic testing to confirm cure of Helicobacter pylori infection after antimicrobial therapy is not completely define d. Objective.-To determine the utility of serologic testing in confirm ing cure of H pylori infection more than 1 year after therapy. Design. -A prospective, before-after interventional trial. Setting.-An outpati ent clinical research laboratory in an academic, urban Veterans Affair s medical center. Participants.-Twenty-three otherwise healthy men and women with active H pylori infection demonstrated by gastric biopsy a nd with positive H pylori serologic findings. Intervention.-A 14-day c ourse of bismuth, tetracycline, and metronidazole. Main Outcome Measur es.-Determination of IgG serum antibodies to H pylori at baseline, 1 m onth, 3 months, and approximately 18 months after completion of therap y compared with serial gastric mucosal biopsy specimens with stains fo r H pylori and for histologic examination as the criterion standard. R esults.-Fifteen (65%) of 23 subjects were cured of their H pylori infe ction as assessed by gastric biopsy, with elimination of gastritis; me dian antibody levels declined from 92.5 U/mL at baseline to undetectab le levels at 18 months. The other 8 subjects (35%) were not cured and had persistent gastritis at 18 months; median antibody levels declined from 130.6 U/mL at baseline to 89.7 U/mL at 18 months. Sensitivity an d specificity of seroconversion (from a positive to negative test resu lt) in detecting cure of H pylori infection were 60% and 100%, respect ively. Conclusion.-Undetectable antibody levels beyond the first year of therapy accurately confirm cure of H pylori infection in initially seropositive healthy subjects, with reasonable sensitivity.