Cost-Effectiveness of Fecal Immunochemical Testing Alone vs Co-Testing With Helicobacter pylori Stool Antigen

Clinical Snapshot

Key Findings

• P Value: Not reported (cost-effectiveness analyses do not conventionally report p-values; PSA used instead)

• Effect Size: Co-testing was dominant (more effective and less expensive) in the base case, with an ICER of −$2,094 per QALY gained (cost-saving). Benefit-cost ratio: 5.08 (approximately 5-fold return on investment in Taiwan). Co-testing remained cost-effective under US cost assumptions at moderate H. pylori prevalence. H. pylori prevalence threshold for cost-effectiveness at $100,000/QALY: 21.9%

• Primary Outcome: Incremental cost-effectiveness ratio (ICER) of invitation to H. pylori stool antigen testing plus FIT vs FIT alone over a 30-year lifetime horizon

• Nnt Or Sensitivity: Co-testing was cost-saving in 65.7% of PSA simulations at Taiwan's willingness-to-pay threshold of $33,365/QALY (1× Taiwan GDP per capita). NNT not reported; BCR of 5.08 is the primary economic summary measure

• Confidence Interval: 95% CI for base-case ICER: $12,359 saved to $7,291 additional cost per QALY

Clinical Application

HpSA testing is a non-invasive, stool-based test that can be co-administered with FIT kits in a population screening programme with minimal additional participant burden. Eradication therapy following positive HpSA requires antibiotic prescribing infrastructure and follow-up confirmation of eradication. Feasibility depends on local H. pylori prevalence, laboratory capacity for HpSA processing, and primary care capacity to manage eradication therapy and confirm cure. Australia has a National Bowel Cancer Screening Programme (NBCSP) using biennial FIT for adults aged 45–74 years, providing an existing infrastructure into which HpSA co-testing could theoretically be integrated. H. pylori prevalence in Australia is estimated at 15–20% in the general population, with higher rates in Aboriginal and Torres Strait Islander communities (up to 70%), recent migrants from high-prevalence regions, and socioeconomically disadvantaged groups. Based on the authors' own sensitivity analysis, co-testing may not be cost-effective at the $100,000/QALY threshold (Australia's approximate WTP) if prevalence falls below 21.9% in the general population — suggesting targeted rather than universal co-testing may be more appropriate in Australia. HpSA tests are not currently listed on the Medicare Benefits Schedule (MBS) for population screening purposes, though 13C-urea breath testing and serology are available. H. pylori eradication regimens (e.g., clarithromycin-based triple therapy or bismuth quadruple therapy) are available via the PBS. The TGA has approved HpSA assays for diagnostic use. RACGP guidelines support H. pylori testing and eradication in symptomatic patients and those with peptic ulcer disease but do not currently recommend population-based screening. Implementation in high-prevalence subpopulations (e.g., First Nations communities, refugee health programmes) warrants dedicated health economic modelling using Australian cost and prevalence data. Adults aged approximately 50–75 years participating in population-based colorectal cancer screening programmes in settings with moderate-to-high H. pylori prevalence (above approximately 22%). Most directly applicable to East Asian populations with established FIT-based screening infrastructure.

Abstract

IMPORTANCE: Helicobacter pylori infection is the leading cause of gastric cancer, yet the economic value of population-based screening and eradication remains uncertain. OBJECTIVE: To project the lifetime health benefits and costs of invitation to 1-time H pylori stool antigen testing added to biennial fecal immunochemical test (FIT) screening compared with FIT alone. DESIGN, SETTING, AND PARTICIPANTS: Lifetime cost-effectiveness analysis conducted using a Markov decision-analytic model to simulate a cohort informed by a pragmatic randomized clinical trial in Changhua County, Taiwan. The model adopted a 30-year time horizon and projected long-term outcomes, including gastric and colorectal cancer mortality, quality-adjusted life-years (QALYs; incorporating both life expectancy and health-related quality of life), and health care expenditures. Costs were evaluated from a societal perspective. One-way and probabilistic sensitivity analyses were performed. Future costs and QALYs were discounted at an annual rate of 3%. EXPOSURES: Helicobacter pylori stool antigen testing plus FIT or FIT alone. MAIN OUTCOMES AND MEASURES: Incremental cost-effectiveness ratio of invitation for H pylori stool antigen testing plus FIT vs FIT alone, measured as the additional cost required to gain 1 QALY per person. Secondary outcomes included net monetary benefit and benefit-cost ratio. RESULTS: Compared with FIT alone, invitation to co-testing was more effective and less expensive (dominant), with a base-case cost-saving incremental cost-effectiveness ratio of $2094 per QALY gained (95% CI, $12 359 saved to $7291 additional cost). This resulted in a positive net monetary benefit, indicating that health benefits exceeded costs, and a benefit-cost ratio of 5.08, indicating an approximately 5-fold return on investment in the Taiwanese population. At a willingness-to-pay threshold of 1 × the Taiwan gross domestic product per QALY ($33 365), invitation to co-testing remained cost-saving in 65.7% of simulations. From a US cost perspective, invitation to co-testing was not cost-saving but remained cost-effective at the trial base-case H pylori prevalence. Sensitivity analyses identified H pylori prevalence as the dominant driver; co-testing exceeded a $100 000-per-QALY threshold when prevalence fell below 21.9%. CONCLUSIONS AND RELEVANCE: In a pragmatic real-world setting with incomplete adherence, invitation to combined H pylori stool antigen testing and FIT was more cost-effective than FIT alone, improving lifetime outcomes and yielding cost savings in Taiwan while remaining cost-effective in higher-cost settings under moderate H pylori prevalence. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01741363.