The cost-effectiveness of screening for Helicobacter pylori to reduce mortality and morbidity from gastric cancer and peptic ulcer disease: a discrete-event simulation model

Evolving Concepts in Helicobacter pylori Management

Helicobacter pylori is the most common chronic bacterial infection worldwide and the most significant risk factor for gastric cancer, which remains a leading cause of cancer-related death globally. H pylori and gastric cancer continue to disproportionately impact racial and ethnic minority and immigrant groups in the United States. The approach to H pylori case-finding thus far has relied on opportunistic testing based on symptoms or high-risk indicators, such as racial or ethnic background and family history. However, this approach misses a substantial proportion of individuals infected with H pylori who remain at risk for gastric cancer because most infections remain clinically silent. Moreover, individuals with chronic H pylori infection are at risk for gastric preneoplastic lesions, which are also asymptomatic and only reliably diagnosed using endoscopy and biopsy. Thus, to make a significant impact in gastric cancer prevention, a systematic approach is needed to better identify individuals at highest risk of both H pylori infection and its complications, including gastric preneoplasia and cancer. The approach to H pylori eradication must also be optimized given sharply decreasing rates of successful eradication with commonly used therapies and increasing antimicrobial resistance. With growing acceptance that H pylori should be managed as an infectious disease and the increasing availability of susceptibility testing, we now have the momentum to abandon empirical therapies demonstrated to have inadequate eradication rates. Molecular-based susceptibility profiling facilitates selection of a personalized eradication regimen without necessitating an invasive procedure. An improved approach to H pylori eradication coupled with population-level programs for screening and treatment could be an effective and efficient strategy to prevent gastric cancer, especially in minority and potentially marginalized populations that bear the heaviest burden of H pylori infection and its complications.

Cost-effectiveness of prevention and early detection of gastric cancer in Western countries

Gastric cancer (GC) is a significant global health problem, with Helicobacter pylori infection estimated to be responsible for 89% of non-cardiac GC cases, or 78% of all GC cases. The International Agency for Research on Cancer has called for Helicobacter pylori test-and-treat strategies in countries with high rates of GC. However, for countries with low rates of GC, such as most Western countries, the balance between benefits, harms and costs of screening is less clear-cut. GC is a disease with a well-characterized precancerous process, providing the basis for primary and secondary prevention efforts. However, rigorous data assessing the impact of such interventions in Western countries are lacking. In the absence of clinical trials, modelling offers a unique approach to evaluate the potential impact of various screening and surveillance interventions. In this paper, we provide an overview of modelling studies evaluating the cost-effectiveness of GC screening and surveillance in Western countries.

Gastric Cancer Incidence and Mortality in French Guiana: South American or French?

PURPOSE

Gastric cancer is a frequent cancer in the tropics. The objective was to review a decade of gastric cancer data, and to study its spatial and temporal trends.

METHODS

The cancer registry of French Guiana compiled exhaustive data on gastric cancer throughout French Guiana between 2005 and 2014. Age-standardized incidence and mortality rates were computed.

RESULTS

With 187 new cases recorded, gastric cancer ranked 6th (4.3%). It was more frequent in men than in women. The median age at diagnosis was 62 years for men and 65 years for women. The incidence rate standardized to the world population over the period 2005-2014 was 14.3 cases of gastric cancer per 100,000 man-years and 7.3 per 100,000 woman-years. The death rate from gastric cancer, standardized to the world population over the period 2005-2014, was 8.6 deaths from gastric cancer per 100,000 man-years and 3.4 per 100,000 women-years. These measures were lower than what is reported in Latin America, similar to Martinique and Guadeloupe-two tropical French territories-and higher than in France.

CONCLUSIONS

Gastric cancer affected more males and the median age was younger than in France. Standardized incidence and mortality rates for gastric cancer in French Guiana were between those of France and those of Latin America, and they were comparable to those of the French West Indies. The downward trend in a context of rapid economic growth suggests further gains that could be achieved by improving electricity, water, and sanitation coverage throughout the territory despite challenging geography, and better access to care and Helicobacter pylori eradication.

Helicobacter pylori eradication therapy to prevent gastric cancer: systematic review and meta-analysis

OBJECTIVES

Gastric cancer is strongly associated with Helicobacter pylori (H. pylori). We conducted a previous systematic review and meta-analysis that suggested eradication therapy reduced future incidence of gastric cancer, but effect size was uncertain, and there was no reduction in gastric cancer-related mortality. We updated this meta-analysis, as more data has accumulated. We also evaluated impact of eradication therapy on future risk of gastric cancer in patients having endoscopic mucosal resection for gastric neoplasia.

DESIGN

We searched the medical literature through February 2020 to identify randomised controlled trials (RCTs) examining effect of eradication therapy on subsequent occurrence of gastric cancer in healthy H. pylori-positive adults, and in H. pylori-positive patients with gastric neoplasia undergoing endoscopic mucosal resection. The control arm received placebo or no treatment. Follow-up was for ≥2 years. We estimated the relative risk (RR) number needed to treat (NNT), and evaluated the disability-adjusted life-years (DALYs) gained from screening from the meta-analysis.

RESULTS

We identified 10 RCTs, seven recruited 8323 healthy individuals, and three randomised 1841 patients with gastric neoplasia. In healthy individuals, eradication therapy reduced incidence of gastric cancer (RR=0.54; 95% CI 0.40 to 0.72, NNT=72), and reduced mortality from gastric cancer (RR=0.61; 95% CI 0.40 to 0.92, NNT=135), but did not affect all-cause mortality. These data suggest that 8 743 815 DALYs (95% CI 5 646 173 to 11 847 456) would be gained if population screening and treatment was implemented globally. In patients with gastric neoplasia, eradication therapy also reduced incidence of future gastric cancer (RR=0.49; 95% CI 0.34 to 0.70, NNT=21). Adverse events were incompletely reported.

CONCLUSION

There is moderate evidence to suggest that H. pylori eradication therapy reduces the incidence of gastric cancer in healthy individuals and patients with gastric neoplasia in East Asian countries. There also appears to be a reduction in gastric cancer-related mortality.

Cost-effectiveness of Helicobacter pylori test and eradication versus upper gastrointestinal series versus endoscopy for gastric cancer mortality and outcomes in high prevalence countries

Background: The latest version of Japanese guidelines for effective secondary prevention of gastric cancer recommend upper gastrointestinal series (UGI) and endoscopy in adults 50 years of age and older. A Helicobacter pylori antibody test and eradication (H. pylori screening) reduces gastric cancer risk. Objective: This study aimed to evaluate the cost-effectiveness of H. pylori screening, compared to UGI and endoscopy in high prevalence countries. Methods: We developed decision trees with Markov models using a healthcare payer perspective and a lifetime horizon. Targeted populations were hypothetical cohorts of asymptomatic individuals at the age of 50, 60, 70 and 80 years. We calculated per-person costs and effectiveness with discounting at a fixed annual rate of 3% and compared incremental cost-effectiveness ratios. Results: H. pylori screening was cost-saving and more cost-effective for individuals at the age of 50, 60, 70, and 80 than UGI and endoscopy. One-way and multiway sensitivity analyses showed the robustness of the cost-effectiveness results. Probabilistic sensitivity analyses using Monte-Carlo simulation for 10,000 trials demonstrated that H. pylori screening was cost-effective 100% of the time at a willingness-to-pay level of US$50,000/QALY gained. Conclusions: H. pylori screening for the adults 50 years of age and older could be cost-effective compared to UGI and endoscopy in high prevalence countries. The main reasons for the superiority of H. pylori screening are that an H. pylori antibody test has a higher sensitivity and specificity than UGI and endoscopy and the benefits to reduce gastric cancer incidence and mortality.

Cost-effectiveness of Helicobacter pylori screening followed by eradication treatment for employees in Japan

Gastric cancer is the third leading cause of cancer death worldwide. Gastric cancer screening using upper gastrointestinal series, endoscopy and serological testing has been performed in population-based (employee-based and community-based) and opportunistic cancer screening in Japan. There were 45 531 gastric cancer deaths in 2016, with the low screening and detection rates.Helicobacter pylori(H. pylori) screening followed by eradication treatment is recommended in high-risk population settings to reduce gastric cancer incidence. The aim of this study was to evaluate the cost-effectiveness ofH. pyloriscreening followed by eradication treatment for a high-risk population in the occupational health setting. Decision trees and Markov models were developed for two strategies;H. pyloriantibody test (HPA) screening and no screening. Targeted populations were hypothetical cohorts of employees aged 20, 30, 40, 50 and 60 years using a company health payer perspective on a lifetime horizon. Per-person costs and effectiveness (quality-adjusted life-years) were calculated and compared. HPA screening yielded greater benefits at the lower cost than no screening. One-way and probabilistic sensitivity analyses using Monte-Carlo simulation showed strong robustness of the results.H. pyloriscreening followed by eradication treatment is recommended to prevent gastric cancer for employees in Japan, on the basis of cost-effectiveness.

Helicobacter pylori management in ASEAN: The Bangkok consensus report

Helicobacter pylori (H. pylori) infection remains to be the major cause of important upper gastrointestinal diseases such as chronic gastritis, peptic ulcer, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. H. pylori management in ASEAN: the Bangkok consensus report gathered key opinion leaders for the region to review and evaluate clinical aspects of H. pylori infection and to develop consensus statements, rationales, and grades of recommendation for the management of H. pylori infection in clinical practice in ASEAN countries. This ASEAN Consensus consisted of 34 international experts from 10 ASEAN countries, Japan, Taiwan, and the United States. The meeting mainly focused on four issues: (i) epidemiology and disease association; (ii) diagnostic tests; (iii) management; and (iv) follow-up after eradication. The final results of each workshop were presented for consensus voting by all participants. Statements, rationale, and recommendations were developed from the available current evidence to help clinicians in the diagnosis and treatment of H. pylori and its clinical diseases.

Population screening and treatment of Helicobacter pylori infection

Helicobacter pylori is an important human pathogen, associated with a substantial burden from both malignant and non-malignant diseases. The bacterium is classed as a human carcinogen, being strongly linked with gastric cancer, the third most common cause of cancer death worldwide and is also associated with common conditions such as dyspepsia and peptic ulcer. Eradication of H. pylori reduces the incidence of gastric cancer and peptic ulcer, as well as the prevalence and costs of managing dyspepsia. Economic analyses suggest that eradication of H. pylori as a means of controlling gastric cancer is cost-effective in high-risk populations. Even in populations at low risk of gastric cancer, there might be other benefits arising from screening and treatment, owing to the effects on non-malignant upper gastrointestinal diseases. However, public health authorities have been slow to consider the benefits of population-based screening and treatment as a means of reducing the morbidity and mortality associated with the infection. There are also concerns about widespread use of eradication therapy, including antimicrobial resistance and a rise in the prevalence of diseases that are negatively associated with H. pylori, such as GERD, Barrett oesophagus, asthma and obesity. This Review summarizes these issues.

A screening program to test and treat for Helicobacter pylori infection: Cost-utility analysis by age, sex and ethnicity

BACKGROUND

The World Health Organization recommends all countries consider screening for H. pylori to prevent gastric cancer. We therefore aimed to estimate the cost-effectiveness of a H. pylori serology-based screening program in New Zealand, a country that includes population groups with relatively high gastric cancer rates.

METHODS

A Markov model was developed using life-tables and morbidity data from a national burden of disease study. The modelled screening program reduced the incidence of non-cardia gastric cancer attributable to H. pylori, if infection was identified by serology screening, and for the population expected to be reached by the screening program. A health system perspective was taken and detailed individual-level costing data was used.

RESULTS

For adults aged 25-69 years old, nation-wide screening for H. pylori was found to have an incremental cost of US$196 million (95% uncertainty interval [95% UI]: $182-$211 million) with health gains of 14,200 QALYs (95% UI: 5,100-26,300). Cost per QALY gained was US$16,500 ($7,600-$38,400) in the total population and 17% (6%-29%) of future gastric cancer cases could be averted with lifetime follow-up. A targeted screening program for Māori only (indigenous population), was more cost-effective at US$8,000 ($3,800-$18,500) per QALY.

CONCLUSIONS

This modeling study found that H. pylori screening was likely to be cost-effective in this high-income country, particularly for the indigenous population. While further research is needed to help clarify the precise benefits, costs and adverse effects of such screening programs, there seems a reasonable case for policy-makers to give pilot programs consideration, particularly for any population groups with relatively elevated rates of gastric cancer.

Helicobacter Pylori and Gastric Cancer: Clinical Aspects

Objective:

Although Helicobacter pylori (H. pylori) is considered as the main etiological factor for gastric cancer, the strategy of screening and treating the oncogenic bacterium is still controversial. The objective was to evaluate the status and progress of the cognition about the relationship between H. pylori infection and gastric cancer from a clinical aspect.

Data Sources:

The data used in this review were mainly from the PubMed articles published in English from 1984 to 2015.

Study Selection:

Clinical research articles were selected mainly according to their level of relevance to this topic.

Results:

Gastric cancer is the fifth most common malignancy and the third leading cause of cancer deaths worldwide. The main etiological factor for gastric cancer is H. pylori infection. About 74.7–89.0% gastric cancer was related to H. pylori infection. Up to date, some regional gastric cancer prevention programs including the detection and treatment of H. pylori infection are under way. Current data obtained from the randomized controlled trials suggest that population-based H. pylori screening and treatment is feasible and cost-effective in preventing gastric cancer; however, a population-based H. pylori eradication campaign would potentially lead to bacterial resistance to the corresponding antibiotics, as well as a negative impact on the normal flora.

Conclusions:

The important questions of feasibility, program costs, appropriate target groups for intervention, and the potential harm of mass therapy with antibiotics must first be answered before implementing any large-scale program.

Peptic ulcer andHelicobacter pylori

As evidence about the relationship between Helicobacter pylori infection and peptic ulcers accumulates, accurate testing and treatment are becoming increasingly important. However, big questions remain about the best strategies for detecting and managing this infection. In this article, the authors discuss the association between H pylori and peptic ulcer disease, the available tests for detecting the infection, and the latest treatment strategies for effective eradication.

Prophylactic use of aspirin: systematic review of harms and approaches to mitigation in the general population

A careful assessment of benefits and harms is required to assess suitability of aspirin as a prophylactic public health measure. However, comprehensive population-level data on harms are lacking. We collected and synthesized age and sex-specific data on harms relevant to aspirin use in average-risk individuals aged 50 years or older. We conducted systematic literature searches to identify baseline rates of gastrointestinal (GI) bleeding, peptic ulcer, major extra-cranial bleeding, and case-fatality rates due to GI bleeding or peptic ulcer in general population. The magnitude of aspirin-associated increase, the prevalence and attributable risk of Helicobacter pylori infection on these events in aspirin users was also assessed. Baseline rates of major extracranial bleeding events and GI complications increase with age; an almost threefold to fourfold increase is observed from age 50-54 to 70-74 years. Low or standard-dose aspirin use increases GI bleeding events by 60% leading to an annual excess of 0.45 and 0.79 GI bleeding events per 1,000 women and men aged 50-54 years respectively. 5-10% of major GI complications are fatal; a clear age dependence--higher fatality in older individuals, is seen. Eradication of H. pylori infection before aspirin use could reduce the incidence of upper GI complications by 25-30%. GI complications are increased by about 60% due to aspirin use but are fatal only in a very small proportion of individuals younger than 70 years of age. Major bleeding events that are comparable in severity to cancer or CVD, are infrequent. Screening and eradication of H. pylori infection could substantially lower aspirin-related GI harms.

Estimates of benefits and harms of prophylactic use of aspirin in the general population

BACKGROUND

Accumulating evidence supports an effect of aspirin in reducing overall cancer incidence and mortality in the general population. We reviewed current data and assessed the benefits and harms of prophylactic use of aspirin in the general population.

METHODS

The effect of aspirin for site-specific cancer incidence and mortality, cardiovascular events was collated from the most recent systematic reviews. Studies identified through systematic Medline search provided data regarding harmful effects of aspirin and baseline rates of harms like gastrointestinal bleeding and peptic ulcer.

RESULTS

The effects of aspirin on cancer are not apparent until at least 3 years after the start of use, and some benefits are sustained for several years after cessation in long-term users. No differences between low and standard doses of aspirin are observed, but there were no direct comparisons. Higher doses do not appear to confer additional benefit but increase toxicities. Excess bleeding is the most important harm associated with aspirin use, and its risk and fatality rate increases with age. For average-risk individuals aged 50-65 years taking aspirin for 10 years, there would be a relative reduction of between 7% (women) and 9% (men) in the number of cancer, myocardial infarction or stroke events over a 15-year period and an overall 4% relative reduction in all deaths over a 20-year period.

CONCLUSIONS

Prophylactic aspirin use for a minimum of 5 years at doses between 75 and 325 mg/day appears to have favourable benefit-harm profile; longer use is likely to have greater benefits. Further research is needed to determine the optimum dose and duration of use, to identify individuals at increased risk of bleeding, and to test effectiveness of Helicobacter pylori screening-eradication before starting aspirin prophylaxis.

A patient-level calibration framework for evaluating surveillance strategies: a case study of mammographic follow-up after early breast cancer

OBJECTIVE

Currently all women who have completed their primary treatment for early breast cancer are invited to receive routine annual mammography. There is no randomized controlled trial evidence to support this schedule, and model-based analysis is required. This paper describes a novel data collection and model calibration process to analyze the cost-effectiveness of alternative follow-up schedules for early breast cancer survivors.

METHODS

A discrete event simulation model describes the progression of early breast cancer after the completion of primary treatment, representing impalpable and palpable recurrence and the detection of impalpable disease via follow-up mammography. Retrospective data from the South Australian Cancer Registry and clinical and administrative hospital databases were linked for 407 postmenopausal women diagnosed with moderate-prognosis early breast cancer from 2000 to 2008. These data formed the basis of a patient-level probabilistic calibration process.

RESULTS

For 50- to 69-year-old survivors, annual follow-up for 5 years, with visits every 2 years thereafter, appears to be cost-effective. For women aged 70 to 79 years at diagnosis, a surveillance schedule similar to general population screening (2 yearly) appears to be most cost-effective if high rates of adherence can be maintained.

CONCLUSIONS

This study demonstrated the potential value of combining linked, retrospective data and decision analytic modeling to provide estimates of costs and health outcomes that are sufficiently robust to inform cancer clinical guidelines and individual patient decisions regarding appropriate follow-up schedules.

Helicobacter pylori antibody patterns in Germany: a cross-sectional population study

BACKGROUND

Helicobacter pylori infection that is usually acquired in childhood and lasts for lifetime is mostly asymptomatic but associated with severe gastrointestinal disease including cancer. During chronic infection, the gastric mucosa is histologically changing. This forces H. pylori to permanent adaptation in its gastric habitat by expression of different proteins which might be reflected in distinctive antibody patterns.

METHODS

To characterize dynamics of the immune response to H. pylori we analysed 1797 sera of a cross-sectional study representative for the German population (age range 1-82 years) with multiplex serology, a fluorescent bead-based antibody binding assay that allows simultaneous and quantitative detection of antibodies. Fifteen recombinant, affinity-purified H. pylori proteins (UreA, GroEL, Catalase, NapA, CagA, CagM, Cagδ, HP0231, VacA, HpaA, Cad, HyuA, Omp, HcpC and HP0305) were used as antigens.

RESULTS

H. pylori seroprevalence (positivity for at least three antigens) was 48% and increased with age from 12% in children <15 years to 69% in females and 90% in males >65 years. Prevalences were highest (>83%) for Omp, VacA and GroEL. For 11 proteins, seroprevalence was higher in males than females (P < 0.05) from age 55 onwards. For all antigens, the median prevalence increase per age decade was stronger in males (8.4%, range 3.8-12.9%) than females (6.1%, range 3.4-10.8%). However, among seropositives the median number of antigens recognized increased from children <15 years to individuals >65 years stronger in females (P = 0.02). Antibody reactivities to GroEL, HyuA, CagM, Catalase, NapA and UreA also increased stronger in females (average 1.7-fold/decade, SD 0.5) than in males (1.5-fold/decade, SD 0.4).

CONCLUSION

H. pylori antibody response accumulates qualitatively and quantitatively with age. This may reflect a lifelong stimulation of the immune response by chronically active infection.

Cost-effectiveness of screening and treating Helicobacter pylori for gastric cancer prevention

Gastric cancer is the second leading cause of cancer-related death worldwide. A meta-analysis of seven randomized controlled trials concluded that Helicobacter pylori eradication reduces gastric cancer incidence by 35%. Current consensus is that H. pylori screening and treatment is cost-effective only in high-risk populations. This paper provides an up-to-date overview of the evidence for cost-effectiveness of H. pylori screening and treatment in different population settings and risk levels for H. pylori infection. Ten unique cost-effectiveness or cost-utility analyses were identified. All found that screening for H. pylori to prevent gastric cancer in the general population costs less than $50,000 per LYG. This finding was robust for differences in H. pylori prevalence, gender and ethnicity. Based on limited evidence, re-treatment (for treatment failure), repeated screening, limiting screening and treatment to those with the CagA phenotype, or universal treatment, does not appear to be cost-effective. However, most included studies failed to consider both the broader benefits as well as the adverse effects of widespread use of antibiotics for H. pylori.

Screening for gastric cancer and surveillance of premalignant lesions: a systematic review of cost-effectiveness studies

BACKGROUND

Cost-effectiveness studies are highly dependent on the models, settings, and variables used and should be based on systematic reviews. We systematically reviewed cost-effectiveness studies that address screening for gastric cancer and/or surveillance of precancerous conditions and lesions.

MATERIALS AND METHODS

A systematic review of cost-effectiveness studies was performed by conducting a sensitive search in seven databases (PubMed, Scopus, Web of Science, Current Contents Connect, Centre for Reviews and Dissemination, Academic Search Complete, and CINAHL Plus), independently evaluated by two investigators. Articles were evaluated for type of study, perspective, model, intervention, incremental cost-effectiveness ratio, clinical or cost variables, and quality, according to published guidelines.

RESULTS

From 2395 abstracts, 23 articles were included: 19 concerning population screening and 4 on following up premalignant lesions. Studies on Helicobacter pylori screening concluded that serology was cost-effective, depending on cancer incidence and endoscopy cost (incremental cost-effectiveness ratio: 6264-25,881), and eradication after endoscopic resection was also cost-effective (dominant) based on one study. Studies on imaging screening concluded that endoscopy was more cost-effective than no screening (incremental cost-effectiveness ratio: 3376-26,836). Articles on follow-up of premalignant lesions reported conflicting results (incremental cost-effectiveness ratio: 1868-72,519 for intestinal metaplasia; 18,600-39,800 for dysplasia). Quality assessment revealed a unanimous lack of a detailed systematic review and fulfillment of a median number of 23 items (20-26) of 35 possible ones.

CONCLUSIONS

The available evidence shows that Helicobacter pylori serology or endoscopic population screening is cost-effective, while endoscopic surveillance of premalignant gastric lesions presents conflicting results. Better implementation of published guidelines and accomplishment of systematic detailed reviews are needed.

Gastric cancer chemoprevention: the current evidence

Chemoprevention may form the cornerstone in the management of gastric adenocarcinoma of the future. Helicobacter pylori eradication and aspirin and/or nonsteroidal anti-inflammatory drug therapy have emerged as front-runner chemotherapeutic agents due to the putative pathogenic mechanisms that they address. Before a population-based chemopreventive strategy can be recommended on a large scale, randomized controlled trials with follow-up of more than 10 years of these 2 agents in populations at high gastric adenocarcinoma risk is urgently awaited.

Economic analysis of esophageal stenting for management of malignant dysphagia

Over half of patients diagnosed with esophageal cancer are unsuitable for curative resection. A significant proportion of these patients will subsequently require palliative stenting to alleviate dysphagia. There is growing consensus in the literature that the deployment of a Self-Expanding Metal Stent is the optimum stenting strategy; however, it remains unclear whether covered or uncovered metal stents are more cost-effective. In order to determine which type of prosthesis is more cost-effective, we compared the different stenting strategies in terms of 1-year stent-related mortality, health-related quality of life, and cost. A decision analytical model was constructed to compare the 1-year stent-related mortality, health-related quality of life, and cost between covered and uncovered stents. Probabilistic sensitivity analysis was performed to quantify the uncertainty associated with our results. Value of Information analysis was performed to assess the value of further research. In order to fully characterize the uncertainty associated with this decision, plastic stents were included in our analysis. Stent-related mortality was slightly lower following covered stent deployment compared with uncovered stent deployment (1.00% vs. 1.26%). Covered stents were more effective by 0.0013 Quality-Adjusted Life Years (Standard Deviation [SD] 0.0013 Quality-Adjusted Life Years). They were also less expensive by $729.58 (SD $390.63). Probabilistic sensitivity analysis suggested that these results were not sensitive to model parameter uncertainty. Plastic stents deployment was $2832.64 (SD $1182.72) more expensive than uncovered metal stent deployment. Value of Information analysis suggests that the maximum value of further research in the UK is $61,124.30. The results of this study represent strong evidence for the cost-effectiveness of covered compared with uncovered self-expanding metal stents for the palliation of patients with malignant dysphagia. The findings support previously published literature asserting the dominance of self-expanding metal stents over plastic stents. Value of Information analysis suggests that further research may not be cost-effective. These findings have significant implication for both current clinical practice and future clinical research.

A Hybrid Cohort Individual Sampling Natural History Model of Age-Related Macular Degeneration: Assessing the Cost-Effectiveness of Screening Using Probabilistic Calibration

Background. Age-related macular degeneration (AMD) is a leading cause of visual impairment and blindness. It is likely that treatment of AMD at earlier stages is more effective than later treatment; thus, screening for AMD should be considered. The aim of this study was to develop a natural history model of AMD to estimate the cost-effectiveness of screening. Methods. A hybrid cohort/individual sampling decision analytic model was developed. Primary data sets, expert elicitation, and data from the literature were used to populate the model. To incorporate joint parameter uncertainty, and to populate unobservable parameters, an innovative form of probabilistic calibration was applied to a range of output parameters. Results. In the reference case, annual screening from age 60 y is the most cost-effective option, although this is subject to high levels of uncertainty. Alternative, age-specific utility values show that screening is predicted to be less cost-effective, assuming interventions that reduce progression to wet AMD moderately improve the cost-effectiveness of screening, whereas the addition of anti—vascular endothelial growth factor therapy for juxtafoveal or subfoveal wet AMD lesions improves the cost-effectiveness of screening significantly. Conclusions. The extent of the uncertainty around the mean results, and the additional resources and possible reorganization of services required to implement screening, indicate that it may be preferable to reduce the level of uncertainty before implementing screening for AMD. Initial actions may be best targeted at assessing how routine data may be used to describe clinical presentation, a screening pilot study, and a secondary costing study.

Calibration methods used in cancer simulation models and suggested reporting guidelines

Increasingly, computer simulation models are used for economic and policy evaluation in cancer prevention and control. A model's predictions of key outcomes, such as screening effectiveness, depend on the values of unobservable natural history parameters. Calibration is the process of determining the values of unobservable parameters by constraining model output to replicate observed data. Because there are many approaches for model calibration and little consensus on best practices, we surveyed the literature to catalogue the use and reporting of these methods in cancer simulation models. We conducted a MEDLINE search (1980 through 2006) for articles on cancer-screening models and supplemented search results with articles from our personal reference databases. For each article, two authors independently abstracted pre-determined items using a standard form. Data items included cancer site, model type, methods used for determination of unobservable parameter values and description of any calibration protocol. All authors reached consensus on items of disagreement. Reviews and non-cancer models were excluded. Articles describing analytical models, which estimate parameters with statistical approaches (e.g. maximum likelihood) were catalogued separately. Models that included unobservable parameters were analysed and classified by whether calibration methods were reported and if so, the methods used. The review process yielded 154 articles that met our inclusion criteria and, of these, we concluded that 131 may have used calibration methods to determine model parameters. Although the term 'calibration' was not always used, descriptions of calibration or 'model fitting' were found in 50% (n = 66) of the articles, with an additional 16% (n = 21) providing a reference to methods. Calibration target data were identified in nearly all of these articles. Other methodological details, such as the goodness-of-fit metric, were discussed in 54% (n = 47 of 87) of the articles reporting calibration methods, while few details were provided on the algorithms used to search the parameter space. Our review shows that the use of cancer simulation modelling is increasing, although thorough descriptions of calibration procedures are rare in the published literature for these models. Calibration is a key component of model development and is central to the validity and credibility of subsequent analyses and inferences drawn from model predictions. To aid peer-review and facilitate discussion of modelling methods, we propose a standardized Calibration Reporting Checklist for model documentation.

[Analysis of the clinical benefits and cost-effectiveness of performing a systematic second-look gastroscopy in benign gastric ulcer]

INTRODUCTION

We analyzed the need to routinely perform a second gastroscopy after an initial diagnosis of benign gastric ulcer.

METHOD

A total of 226 consecutive cases of gastric ulcer were reviewed. Sensitivity (S), specificity (Sp), positive and negative predictive value (PPV and NPV) and the accuracy of the initial gastroscopy plus biopsy were analyzed, both overall and according to the initial endoscopist's experience (attending or resident physician). The diagnostic accuracy of the initial and second-look gastroscopies was compared. The number of second endoscopies required to diagnose a new case of malignant gastric ulcer and their cost was calculated, both overall and according to the endoscopist's experience.

RESULTS

There were 178 benign ulcers (79%) and 48 malignant ulcers (21%). The initial gastroscopy (S: 87.2%; Sp: 100%; PPV: 100%; PNV: 96.7%; accuracy: 96.7%) was performed by an attending physician in 74% of the patients and by a resident physician in the remaining 26%. Diagnostic accuracy was higher for attending physicians than for residents (98.2% vs. 94.8%; p=0.18). The accuracy of second-look endoscopy was 100%, with a significant improvement when compared with the initial procedure (p=0.035). Three new cases of MALT lymphoma and three new cases of gastric adenocarcinoma were diagnosed and could be treated with curative intent. The number of second gastroscopies required to diagnose a new case of malignant gastric ulcer and their economic cost was: 37.3 (4,675 Euros) for the whole group, 55.2 (6,845 Euros) for attending physicians and 19.3 (2,393 Euros) for residents.

CONCLUSIONS

Initial gastroscopy showed high diagnostic accuracy, which was slightly lower when performed by resident physicians. Second-look gastroscopy significantly improved the results, confirming the clinical benefit of this procedure in diagnosing potentially curable malignant lesions. The mean cost of each new diagnosis of malignancy was 4,675 Euros, which was three times lower if the initial gastroscopy was performed by a less experienced endoscopist.

Eradication therapy for Helicobacter pylori

Eradication therapy for Helicobacter pylori is recommended in a number of clinical conditions. In this article, we discuss the epidemiology and cellular mechanisms that result in antimicrobial resistance, the results of current eradication therapies, and new approaches to the management of Helicobacter pylori infection.

Systematic review: Helicobacter pylori eradication for the prevention of gastric cancer

BACKGROUND

Helicobacter pylori is recognized as one of the most significant risk factors for gastric cancer, and H. pylori eradication has been proposed as a possible primary chemo-preventive strategy to reduce gastric cancer incidence.

AIM

To evaluate the available evidence on the efficacy of H. pylori eradication in the prevention of gastric cancer.

METHODS

Epidemiological, observational and interventional studies, as well as decisional models, were taken into account in this review.

RESULTS

Large-scale epidemiological studies clearly link H. pylori infection with non-cardia gastric cancer. Current evidence suggests that, in a subpopulation of treated subjects, H. pylori eradication prevents the progression of preneoplastic lesions. Studies that have attempted to evaluate the effect of H. pylori eradication on the incidence of gastric cancer have not provided definitive answers. H. pylori eradication seems to reduce the incidence of gastric cancer in patients without baseline precancerous gastric lesions. Decisional models suggest that H. pylori screening could be cost-effective, but there is not yet sufficient evidence to support the setting up of a general screening programme.

CONCLUSION

Helicobacter pylori eradication is a plausible intervention for gastric cancer prevention; however, it seems to be relevant in only a subset of subjects.

Helicobacter pylori eradication for the prevention of gastric cancer

Even though Helicobacter pylori infection is an obvious cause of chronic non-atrophic and atrophic gastritis, as well as gastric dysplasia and cancer, several recent controlled intervention trials for the prevention of gastric cancer by H. pylori eradication have yielded disappointing results. They showed that cancer eradication may still appear in relatively high frequency after successful treatment of H. pylori. One explanation for this observation is that H. pylori treatment has less influence in development of gastric cancer in atrophic gastritis than in development of cancers in non-atrophic gastritis, and that eradication does not prevent the progression of precancerous lesions and small invisible early cancers to overt tumors. Noteworthy however, the available intervention trials show that gastric cancer can be prevented by H. pylori treatment in patients with non-atrophic gastritis. Trials with higher number of patients, with longer follow-up periods, and with more careful controlling of cancer type and underlying gastric mucosal conditions are needed.

Helicobacter pylori infection and gastric cancer

Screening cannot yet be recommended

Helicobacter pylori eradication has the potential to prevent gastric cancer: a state-of-the-art critique

Helicobacter pylori infection continues to play a key role in gastric diseases. Colonization of the gastric mucosa with the bacterium invariably results in the development of chronic gastritis and subsets of patients have a progression of the chronic gastritis to either ulcer or cancer. Epidemiological evidence indicates that the proportion of all gastric cancers attributable to H. pylori infection, and hence potentially preventable upon elimination of this risk factor, is somewhere in the range of 60% to 90%. This portends significant benefit in terms of morbidity and mortality, not least in populations with high prevalence of H. pylori infection coupled with high incidence of gastric cancer. The effect of prophylactic H. pylori eradication on gastric cancer incidence in humans remains unknown, however. Results from randomized trials are eagerly awaited, but availability of strong conclusive results may take many years. A growing number of studies show considerable variation in risk for gastric cancer development, depending on H. pylori strain type and the genetic predisposition of the host. There is also a remote possibility that elimination of the infection may have adverse health implications (e.g., antibiotic resistance), and therefore "simple" risk stratification and targeted chemoprevention is required. Based on "in depth" evidence presented at this workshop, the majority of the scientific task force favored a search-and-treat strategy in first-degree relatives of gastric cancer patients and an overwhelming majority felt that a more general screen-and-treat strategy should be focused in the first instance on a population with a high incidence of H. pylori-associated diseases.

Helicobacter pylori eradication in the management of patients with idiopathic thrombocytopenic purpura

PURPOSE

To investigate the relation between Helicobacter pylori infection and the clinical features of idiopathic thrombocytopenic purpura (ITP), and to examine the effects of H. pylori eradication on platelet counts.

METHODS

A(13)C urea breath test for H. pylori infection was performed in a cohort of 137 consecutive patients with ITP. Patients who tested positive received standard eradication therapy if their platelet count was <50 x 10(9)/L or if they had symptoms of dyspepsia.

RESULTS

H. pylori infection was detected in 64 patients (47%), and was not associated with dyspepsia or other clinical or laboratory features. Eradication therapy was successfully administered to 52 patients. Platelet responses were observed in 17 (33%) of these patients, which lasted for more than 1 year in 11 patients. Duration of ITP was shorter among responders than nonresponders. Only one response was observed among patients with severe thrombocytopenia (platelet count <30 x 10(9)/L).

CONCLUSION

The prevalence of H. pylori infection in patients with ITP is similar to that found in the general population. Infection is not associated with distinctive features of the disease. H. pylori eradication may improve the platelet counts in adults in whom the ITP is of recent onset and in those with less severe degrees of thrombocytopenia, but was not effective in patients with chronic severe ITP.

Assessing the costs, benefits, cost-benefit ratio, and cost-effectiveness of marital and family treatments: why we should and how we can

The vast majority of outcome studies examining the effects of marital and family treatments focus exclusively on indicators of and changes in familial functioning and individual members' psychosocial adjustment, but fail to measure, report, or analyze treatment costs, benefits, cost-benefit ratio, or cost-effectiveness. Because of growing concerns about spiraling health care costs, clinical and economic outcomes constitute equally important and complementary aspects of any evaluation of marital and family treatments. The twofold purpose of this article is to define different components of cost analyses of health-related interventions, including marital and family treatments, and to describe methods for calculating and integrating clinical and cost outcome information when evaluating marital and family treatments. There are significant opportunities to promote the use of such treatments by conducting and reporting the results of cost analyses.

Cost-benefit analysis of Helicobacter pylori screening

BACKGROUND

Helicobacter pylori screening may markedly reduce mortality and morbidity in the decades ahead.

AIMS

This study explores the costs and benefits of population-based H. pylori screening in terms of health care cost taking into account all relevant H. pylori-related diseases.

MATERIAL AND METHODS

The computer-based decision analysis compared two strategies: (1) screen for H. pylori and treat those individuals who test positive, and (2) do not screen for H. pylori, and test and treat H. pylori only if related clinical symptoms appear. The model estimated the discounted H. pylori-related accumulative health care costs from screening age to death in both strategies. The baseline case estimates cost-benefit for screenees aged 15-45 years. The main outcome measure is the incremental health care cost per case in the screening compared with the no-screening alternative. The probability estimates were obtained from the Finnish Vammala H. pylori screen and treat project, including 5288 subjects in the years 1996-1998, published studies, national statistics and hospitals' internal accounts.

RESULTS

The incremental cost per case was 26 US dollars in the screening compared with the no-screening alternative. It was lowest in the group aged 45 years, where H. pylori screening showed cost savings per case.

CONCLUSIONS

H. pylori screening is more favourable in the older age cohorts. The estimated cost per screenee can be considered to be very acceptable if the current pathophysiological evidence on the potential effects of H. pylori eradication are confirmed in the future. However, there is uncertainty about the possible negative effect of eradicating H. pylori infection on gastro-esophageal reflux disease and esophageal adenocarcinoma. This could change the balance of benefits against risks of eradicating H. pylori infection.

Helicobacter pylori public health implications

Population Helicobacter pylori screening and treatment has the potential to dramatically reduce global gastric cancer mortality. There is overwhelming evidence that the infection is a major cause of distal gastric adenocarcinoma. There is also randomized controlled trial evidence that H. pylori eradication reverses or ameliorates histological changes in the gastric mucosa that are important in carcinogenesis. Preliminary randomized controlled trial data suggest that screening and treatment may reduce the risk of gastric cancer although the number of cancer cases was small. Population H. pylori screening and treatment will also reduce mortality from peptic ulcer complications and reduce the burden of dyspepsia in the community. The reduction in health service dyspepsia costs means that this could be the first programme to pay for itself. From a scientific perspective, we still have insufficient evidence to conclude the benefits of population H. pylori screening are greater than the possible harms and we need more randomized controlled trial data. From a public health perspective however, sometimes screening programmes are developed with imperfect information. The medical community should be consistent and if we are instituting other population screening programmes without randomized controlled trial evidence then H. pylori testing and treatment should also be considered.

The exploding worldwide cancer burden: the impact of cancer on women

Although age-adjusted cancer death rates have started to decline in the United States and other developed nations - thanks in large part to widespread screening programs that detect cancers at early, treatable stages - cancer in developing countries is on the rise. Ironically, rising life expectancy in those nations along with the adoption of 'Western' lifestyles will leave many more people vulnerable to cancer. Unfortunately, the early detection tools and treatment technology that have helped control cancer in wealthier lands are often not readily available in many other countries. Much of this increased cancer burden will take the form of cancers that affect women - not only breast, cervical, and other gynecologic cancers but colorectal cancer, lung cancer, and other malignancies related to tobacco. Physicians specializing in cancer care for women need to be alert to every opportunity to improve cancer screening and prevention among the growing, aging populations of less-developed countries. Less precise but less costly and more widely available screening techniques may save thousands more lives than the most sophisticated technology because low-cost programs can be applied widely instead of being reserved for a fortunate few. In addition, education and prevention efforts directed toward tobacco use need to be put in place to help stem an epidemic of tobacco-related cancers that has largely peaked in developed countries but looms ominously in the future of developing nations.

Review article: impact of Helicobacter pylori on society-role for a strategy of 'search and eradicate'

Helicobacter pylori infection is causally related to gastric cancer, a malignancy associated with high morbidity and poor prognosis, and to peptic ulcer disease, a disease with high morbidity and modest mortality. Theoretically, H. pylori eradication is the most practical means of preventing gastric cancer and peptic ulcer disease. From a public policy perspective, the current evidence is insufficient to assess accurately the magnitude of the benefits of a universal 'search and treat' approach. Nonetheless, it is possible to identify high-risk patients for whom testing for the presence of H. pylori infection, with the intention-to-treat infected individuals is currently indicated. This list includes patients with ulcers or dyspepsia, first-degree relatives of patients with peptic ulcer or gastric cancer, gastric cancer patients after potentially curative resection of their gastric cancer, patients in whom long-term acid antisecretory therapy or long-term nonsteroidal anti-inflammatory drug therapy (including low-dose aspirin) is planned, and finally those who desire testing. Population screening among asymptomatic individuals with a high risk of gastric cancer, such as Korean- and Japanese-Americans, appears logical, but from a public health perspective should be done as a component of controlled intervention studies. There are no known H. pylori infections without risk of a symptomatic outcome, therefore screening represents a rational strategy for cancer prevention. Adoption of such a policy will require carefully balancing the costs of the programme with its benefits.