Cost effectiveness analysis of population-based serology screening and 13C-Urea breath test for Helicobacter pylori to prevent gastric cancer: A markov model

Table 1 Parameter estimates in the base-case analysis

Input variable	Base-case analysis	Range	Ref.
Incidence and prevalence rates
Age-specific prevalence of H pylori (%)	20.0-43.3	-	[10]
Age-specific prevalence of gastric cancer per 100 000	3-342	-	[17]
Gastric cancer in distal stomach (%)	60	50-80	[7]
Relative risk of gastric cancer in persons with H pylori infection	3.6	2-12	[7]
Age-specific mortality from age of 25, per 1000	0.5-50.6	-	[16]
Gastric cancer death in deaths from all causes (%)	2.27	2.20-2.33	[14,17]
Survival rate of gastric cancer after treatment (%)			[19]
1-yr	54.2	51-58
2-yr	41.8	38-45
3-yr	37.9	34-42
4-yr	34.0	30-38
5-yr	30.5	27-35
Screening and treatment variables (%)
H pylori serology screening sensitivity	93	82-95	[10]
H pylori serology screening specificity	79	70-92	[10]
H pylori13C-Urea breath test sensitivity	97.9	90-100	[11]
H pylori13C-Urea breath test specificity	95.8	90-100	[11]
Effectiveness of H pylori eradication	92.0	87-98	[21]
Probability of adverse effects related to eradication therapy necessitating medical intervention	2.5	2-5	[6]
Annual H pylori infection rate	1.0	1-3	[6,26]
Excess gastric cancer risk reduction attributable to H pylori eradication	30	0-100	[6]
Cost variables (2006USD)1
H pylori serology screening	26	10-50
H pylori13C-urea breath test	83	60-100
H pylori eradication (triple therapy)	30	20-50
Gastric cancer treatment per annum	4358	328-59 000
Eradication-related adverse effects	50	5-100
Other variables
Annual discount rate for costs and effectiveness (%)	3	0-7	[19,29]
Life expectancy, years	77	76-80	[14]
Utility
H pylori non-infected	1.00	0.95-1.00	[26]
H pylori infected	0.90	0.80-1.00	[26]
Gastric cancer	0.38	0.13-0.65	[26]

Triple therapy: Rabeprazole 20 mg, amoxicillin 1000 mg, and clarithromycin 500 mg, twice a day for 4 d.

¹All costs were estimated from the records of local public hospitals.

Table 2 Incremental cost-effectiveness ratios of screening strategies at age 40 yr (compared to no screening strategy unless stated)

US$/QALY	Base-case		Best-case1		Worst-case1
	Serology	UBT	Serology	UBT	Serology	UBT
ICER per life year saved	16 166	38 792	Dominant	Dominant	389 728	640 000
		477 0792		Dominant2		5 645 4492
ICER per QALY gained	13 571	32 525	Dominant	Dominant	324 773	560 000
		390 3372		Dominant2		Dominated2

ICER: Incremental cost-effectiveness ratio; QALY: Quality-adjusted life year; UBT: ¹³C-Urea breath test.

¹Variables modified in best and worst-case analyses were, gastric cancer risk reduction by eradication (100% and 10%, respectively), relative risk (12 and 2), cost of annual gastric cancer treatment ($59 000 and $328), cost of the serology screening ($10 and $50), cost of the UBT ($60 and $100), and annual discount rate (0% and 7%);

²The ICER was calculated by comparing the UBT with the serology screening.