Noninvasive Helicobacter pylori testing for the "test-and-treat" strategy: a decision analysis to assess the effect of past infection on test choice.

BACKGROUND: Clinical guidelines support a noninvasive Helicobacter pylori "test-and-treat" strategy for individuals with uncomplicated dyspepsia. However, consensus is lacking regarding the preferred noninvasive testing method.
OBJECTIVE: To use decision analytic modeling to estimate the clinical and economic outcomes associated with noninvasive tests designed to detect either H pylori antibody or active H pylori infection.
DESIGN: Decision analytic model. PATIENTS: A simulated patient cohort with uncomplicated dyspepsia.
INTERVENTIONS: The simulated dyspepsia cohort underwent antibody testing or testing to detect active H pylori infection (active testing). Individuals testing positive received eradication therapy. MAIN OUTCOME MEASURES: Appropriate and inappropriate treatment prescribed, cost per patient treated, incremental cost per unnecessary treatment avoided.
RESULTS: Active testing led to a substantial reduction in unnecessary treatment for patients without active infection (antibody, 23.7; active, 1.4 per 100 patients) at an incremental cost of $37 per patient. The clinical advantage and cost-effectiveness of active testing was enhanced as the percentage of individuals with a positive antibody test result from past, but not current, infection increased.
CONCLUSIONS: Active testing for H pylori infection significantly decreases the inappropriate use of antimicrobial therapy when compared with antibody testing. The advantages of active testing should be enhanced as the widespread use of antimicrobial agents increases the proportion of patients with antibody to H pylori, but without active infection.