Table 1.

 Characteristics of randomised controlled trials of H pylori eradication therapy versus placebo in the prevention of gastric cancer

Study	Location	Method to confirm H pylori infection	Sample size (No receiving H pylori eradication therapy)	Characteristics of participants	% with pre-neoplastic lesions* at baseline	H pylori eradication therapy regimen	Eradication rate (%)†	Last point of follow-up	Method to detect gastric cancer cases	Methodology
Correa 2000 22 and Correa 2001 35	2 communities in Narino Province, Colombia	Histological examination‡	852 (437)	Mean (range) age 51.1 (29-69) years, 46.1% men	100	Bismuth subsalicylate 262 mg, amoxicillin 500 mg, metronidazole 375 mg thrice daily for 2 weeks	58.0	6 years	Histological examination‡ at 6 years	Method of randomisation and concealment of allocation stated. Unblinded
Leung 2004 28 and Zhou 2008 27	11 villages in Yantai County, Shandong Province, China	Histological examination and rapid urease testing‡	Leung: 587 (295) Zhou: 552 (276)	Mean (range) age 52.0 (35-75) years, 47.8% men	33.7	Omeprazole 20 mg, amoxicillin 1 g, clarithromycin 500 mg twice daily for 1 week	55.6	Leung: 5 years Zhou: 10 years	Histological examination‡ at 2, 5, 8, and 10 years	Method of randomisation and concealment of allocation stated. Double blind
Wong 2004 24	7 villages in Changle County, Fujian Province, China	Histological examination and rapid urease testing‡	1630 (817)	Mean (range) age 42.2 (35-65) years, 54.0% men	37.7	Omeprazole 20 mg, co-amoxiclav 750 mg, metronidazole 400 mg twice daily for 2 weeks	83.7	7.5 years	Histological examination‡ at 7.5 years or, if diagnosed before 7.5 years, review of clinical records and pathology specimens by three blinded clinicians	Method of randomisation and concealment of allocation stated. Double-blind
Saito 2005 23	145 centres in Japan	Not reported	692 (379)	Mean age not reported (range 20-59 years), proportion men not reported	Not reported	Lansoprazole 30 mg, amoxicillin 1.5 g, clarithromycin 400 mg once daily for 1 week	74.4	≥4 years	Histological examination‡ at ≥4 years	Method of randomisation, concealment of allocation, and blinding not stated
You 200632 and Ma 2012 26	13 villages in Linqu County, Shandong Province, China	Serological testing	2258 (1130)	Mean (range) age 46.8 (35-64) years, 50.0% men	64.0	Omeprazole 20 mg and amoxicillin 1 g twice daily for 2 weeks	73.2	14.7 years	Histological examination‡, clinical, laboratory, or pathological data	Method of randomisation and concealment of allocation stated. Double blind
Wong 2012 25	12 villages in Linqu County, Shandong Province, China	13Carbon-urea breath testing	513 (255)	Mean (range) age 53.0 (35-64) years, 46.4% men	100	Omeprazole 20 mg, amoxicillin 1 g, clarithromycin 500 mg twice daily for 1 week	63.5	5 years	Histological examination‡ at 5 years	Method of randomisation and concealment of allocation stated. Double blind

*Defined as gastric atrophy, intestinal metaplasia, or dysplasia.

†True intention-to-treat analysis, with all drop-outs assumed to have failed eradication therapy.

‡Examination or testing of gastric biopsies obtained from upper gastrointestinal endoscopy.