Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Eradication rates
RCT 3-armed trial	60 people with dyspepsia and persistent H pylori infection after treatment with amoxicillin-based or metronidazole-based triple regimens	Eradication rates 15/22 (68%) with quadruple regimen for 7 days 4/12 (33%) with repeat triple regimen for 7 days	P = 0.02 for quadruple regimen v repeat triple regimen (7 days)	Effect size not calculated	quadruple regimen
RCT 3-armed trial	60 people with dyspepsia and persistent H pylori infection after treatment with amoxicillin-based or metronidazole-based triple regimens	Eradication rates 15/22 (68%) with quadruple regimen for 7 days 16/22 (73%) with repeat triple regimen for 14 days	P = 0.71 for quadruple regimen v repeat triple regimen (14 days)		Not significant
RCT	48 people with persistent H pylori infection after treatment with a triple regimen	Eradication rates 20/28 (71%) with 14-day quadruple regimen 15/20 (75%) with 14-day triple regimen	P = 0.78		Not significant
RCT	84 people with persistent H pylori infection after treatment with a metronidazole-based triple regimen	Eradication rates 27/40 (68%) with 7-day quadruple regimen 19/44 (43%) with 7-day triple regimen	P = 0.03 The RCT was terminated early (after recruiting 84 people); see further information on studies for full details	Effect size not calculated	quadruple regimen