Cowling, BJ

Schooling, CM

Wong, OL

Hong Kong Medical Journal

HKU Scholars Hub

TitleCost-effectiveness of Helicobacter pylori screening andtreatment for gastric cancer in Hong Kong: a decision analyticapproachAuthor(s) Wong, OL; Schooling, CM; Cowling, BJCitation Hong Kong Medical Journal, 2014, v. 20 n. 6, Suppl. 7, p. S13-S15Issued Date 2014URL http://hdl.handle.net/10722/210990Rights Hong Kong Medical Journal. Copyright © Hong Kong Academyof Medicine Press.13Hong Kong Med J  ⎥  Volume 20 Number 6 (Supplement 7)  ⎥  December 2014  ⎥  www.hkmj.orgK e y  M e s s a g e s 1. A state-transition Markov model was developed to evaluate the cost-effectiveness of Helicobacter pylori screening and treatment in Hong Kong Chinese people, and to evaluate the uncertainty surrounding choice of strategies and the value of further research on the decision to initiate a mass screening programme.2. A decision analytic framework and a societal perspective were adopted. The least costly and non-dominated strategy was H pylori serologic testing, followed by treating those positive for H pylori, with no follow-up testing. Its incremental cost-effectiveness ratio was US$20 547 for men and HK$26 840 for women per life year saved or Cost-effectiveness of Helicobacter pylori screening and treatment for gastric cancer in Hong Kong: a decision analytic approachIntroductionIn Hong Kong, gastric cancer is the fourth leading cause of cancer-related death following lung, colorectum, and liver cancer. Eradication of Helicobacter pylori may reduce the incidence of gastric cancer.1 This study estimated the cost-effectiveness of H pylori screening and treatment in Hong Kong Chinese people, and evaluated the uncertainty surrounding choice of strategies and the value of further research on the decision to initiate a mass screening programme.Methods Study instruments and cost-effectiveness analysesThis study was conducted from December 2009 to November 2011. A state-transition Markov model was developed to simulate H pylori screening and treatment as well as gastric cancer diagnosis and treatment in Hong Kong Chinese people aged 20 years for the next 60 years. Participants were followed up throughout their lifetime. Disease progression could vary by H pylori status, sex, and age. According to a gastric carcinogenesis model,2 the natural history of non-cardia intestinal-type gastric adenocarcinomas was characterised as a progression of yearly transitions among various health states (Fig), including normal gastric mucosa, gastritis, gastric atrophy, intestinal metaplasia, Hong Kong Med J 2014;20(Suppl 7):S13-5HHSRF project number: 07080861IOL Wong *, CM Schooling, BJ CowlingIOL Wong *, CM Schooling, BJ CowlingSchool of Public Health, The University of Hong Kong* Principal applicant: BJ Cowling Corresponding author: iolwong@hku.hkdysplasia, early gastric cancer, distant gastric cancer, death from gastric cancer, and death from other causes. A cohort of individuals were distributed to either H pylori–positive or H pylori–negative precancerous health states. They could remain in one state or transit to other states at rates according to local-specific data and/or consensus from the literature. A cohort of 100 000 cancer-free 20-year-old people over a 60-year span was modelled. It was assumed that gastric cancer deaths could only occur in those in the metastatic state. It was assumed that the effectiveness of H pylori treatment depends on the absence of advanced precancerous lesions and that treatment reduces disease progression probabilities in those with gastritis and atrophy.3-5 Our model was based on a randomised controlled trial in a Japanese population evaluating the effectiveness of H pylori treatment to prevent (metachronous) cancers among early gastric cancer patients after endoscopic mucosal resection.1 Three strategies were evaluated: (1) no screening or treatment, (2) H pylori serologic testing, followed by treating those positive for H pylori, with no follow-up testing, (3) H pylori serologic testing, followed by treating those positive for H pylori, and confirming H pylori eradication using a C-urea breath test, and retreating those who were positive.  Four major direct medical costs were considered: the cost of screening for H pylori, the cost of treatment for H pylori, the one-time cost of invasive HEALTH AND HEALTH SERVICES RESEARCH FUNDUS$17 886 for men and HK$23 905 for women per quality-adjusted life year (QALY) saved, compared with no screening or treatment.3. H pylori screening and treatment could be cost-effective based on the threshold of US$50 000 per QALY.  #  Wong et al #14 Hong Kong Med J  ⎥  Volume 20 Number 6 (Supplement 7)  ⎥  December 2014  ⎥  www.hkmj.org Hong Kong Med J  ⎥  Volume 20 Number 6 (Supplement 7)  ⎥  December 2014  ⎥  www.hkmj.orgcancer treatment, and the cost of terminal care during the final 6 months before death. The cancer treatment cost included diagnosis (eg endoscopy), major surgical procedure (eg gastrectomy), hospitalisation after surgery, chemotherapy, and staff costs. The first-line treatment for H pylori (a 14-day course of proton pump inhibitor, clarithromycin, and amoxicillin) was used. The costs of treatment were estimated based on per unit/month drug price and fees and charges in a public hospital. The terminal costs were calibrated according to the trajectory of US cancer costs. Other major non-health care costs were also considered, including transportation and time costs. All costs were adjusted to the 2012 level. Strategies that were less effective and more costly than a competing strategy were eliminated by simple dominance. Comparative performance of the remaining screening strategies was measured by the incremental cost-effectiveness ratio (ICER). Those that were less effective and had a higher ICER were ruled out by extended dominance and eliminated, and the ICERs of the remaining strategies were recalculated.  A societal perspective was adopted. Recommendations of the Panel on Cost-Effectiveness in Health and Medicine were used in performing cost-effectiveness calculations.Sensitivity analysis A probabilistic sensitivity analysis was conducted to examine uncertainty surrounding choice of strategies. Clinical and cost parameters were specified with appropriate probabilistic distributions, and cost-effectiveness results associated with selecting values at random from the distributions were used in a Monte Carlo simulation of the model with 1000 runs. Based on the simulated cost-effectiveness results, a cost-effectiveness acceptability curve was constructed to present the uncertainty of the ICER across different values of the ceiling ratios (ie acceptability willingness-to-pay thresholds). The uncertainty that potentially existed in decision and the model parameters in value of information analyses were assessed. That is, the uncertainty surrounding choice of strategies and whether further research could add value to the decision of initiating a population-wide screening programme were evaluated, as was the expected value of perfect information (EVPI) for the entire cost-effectiveness model.6 FIG.  State transition diagram for the Helicobacter pylori screening modelNormal GastritisAtrophyDysplasiaIntestinalmetaplasiaEarlygastriccancerDistantgastriccancerDied fromgastriccancerDied fromothercausesHigher for H pylori+Equal for H pylori+    and H pylori-*	 Assuming	health-related	utilities	of	0.9	and	0.3	for	early	and	advanced	invasive	cancer	for	the	remaining	time	spent	in	the	same	state†	 Relative	to	the	less	costly,	non-dominated	strategy	aboveTABLE.  Helicobacter pylori screening and treatment strategies for a cohort of 100 000 Hong Kong Chinese people aged 20 years for the next 60 years*Strategy* Projected total mortality in the next 60 yearsProjected gastric cancer-related mortality in the next 60 yearsLifetime costs (million US$)Life years Incremental cost-effectiveness ratio†Cost per life year savedCost per quality-adjusted life year savedMenNo screening or treatment 95 100 814 23.73 5 970 700Screening and treatment 95 091 773 35.03 5 971 250 20 547 17 886Screening, treatment, and rescreening 95 088 759 54.03 5 971 432 104 463 90 712WomenNo screening or treatment 86 962 520 14.99 6 546 824Screening and treatment 86 955 494 26.29 6 547 245 26 840 23 905Screening, treatment, and rescreening 86 953 486 45.29 6 547 375 146 341 130 239Hong Kong Med J  ⎥  Volume 20 Number 6 (Supplement 7)  ⎥  December 2014  ⎥  www.hkmj.org#  Cost-effectiveness of Helicobacter pylori screening for gastric cancer  # 15Hong Kong Med J  ⎥  Volume 20 Number 6 (Supplement 7)  ⎥  December 2014  ⎥  www.hkmj.orgResults Cost-effectiveness and associated uncertaintyCompared with no screening or treatment, screening and treatment for H pylori resulted in a gain in life expectancy of 1.2 to 2 days at an incremental cost of US$113 to US$303 per person (Table). The most cost-effective (non-dominated) strategy was H pylori serologic testing, followed by treating those positive for H pylori, with no follow-up testing. Its ICER was US$20 547 for men and HK$26 840 for women per life year saved or US$17 886 for men and HK$23 905 for women per quality-adjusted life year (QALY) saved, compared with no screening or treatment. In probabilistic sensitivity analyses, the probability of the ICER being below a threshold of US$50 000 per life year saved was 51.9% for men and 50.7% for women. Expected value of perfect informationThe results of the model were subject to limited uncertainty (cost per man/woman=US$825/US$790). The EVPI for the patient populations was estimated to be US$13.4 million over 40 years if a willingness-to-pay threshold was US$50 000 per life year saved.DiscussionThe most cost-effective strategy was H pylori serology testing, followed by antibiotic treatment for those positive, with no follow-up testing. The probability sensitivity analyses and the EVPI analyses showed the robustness of the results by considering several dimensions of uncertainty. The state-transition model captured the natural history of non-cardia intestinal-type gastric adenocarcinoma, and reflected the role of H pylori infection in the pathogenesis of gastric cancer. A potential limitation of this study was that we did not have aggregate local stage-specific treatment costs for invasive gastric cancer, and instead relied on individual itemised cost data. In addition, we did not evaluate the full spectrum of screening strategies for H pylori (eg screening at different ages).  This mathematical decision analytic model could provide insight about the long-term outcomes and the cost-effectiveness of H pylori screening and treatment strategies. AcknowledgementThis study was supported by the Health and Health Services Research Fund, Food and Health Bureau, Hong Kong SAR Government (#07080861). References1. Fukase K, Kato M, Kikuchi S, et al. Effect of eradication of Helicobacter pylori on incidence of metachronous gastric carcinoma after endoscopic resection of early gastric cancer: an open-label, randomised controlled trial. Lancet 2008;372:392-7.2. Correa P. Human gastric carcinogenesis: a multistep and multifactorial process—First American Cancer Society Award Lecture on Cancer Epidemiology and Prevention. Cancer Res 1992;52:6735-40.3. Wong BC, Lam SK, Wong WM, et al. Helicobacter pylori eradication to prevent gastric cancer in a high-risk region of China: a randomized controlled trial. JAMA 2004;291:187-94.4. Correa P, Fontham ET, Bravo JC, et al. Chemoprevention of gastric dysplasia: randomized trial of antioxidant supplements and anti-helicobacter pylori therapy. J Natl Cancer Inst 2000;92:1881-8.5. You WC, Brown LM, Zhang L, et al. Randomized double-blind factorial trial of three treatments to reduce the prevalence of precancerous gastric lesions. J Natl Cancer Inst 2006;98:974-83.6. Claxton KP, Sculpher MJ. Using value of information analysis to prioritise health research: some lessons from recent UK experience. Pharmacoeconomics 2006;24:1055-68. 

Cost-effectiveness of Helicobacter pylori screening and treatment for gastric cancer in Hong Kong: a decision analytic approach

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Cost-effectiveness of Helicobacter pylori screening and treatment for gastric cancer in Hong Kong: a decision analytic approach

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