Table 6.

Risk of bias assessment of randomised placebo-controlled trials.

Citation	Selection Bias		Performance Bias	Detection Bias	Attrition Bias	Reporting Bias
	Random Sequence Generation	Allocation Concealment	Blinding of Participants & Personnel	Blinding of Outcome Assessment	Incomplete Outcome Data	Selective Reporting
[45,46]	low	low	low	low	low	low
[47]	low	unclear *	low	moderate †	low	unclear #

* Patients allocated to either 7 days of twice daily Helicobacter eradication triple-therapy or 15 days of a twice daily allopurinol pill. All participants “received the same number of tablets”, but 7 (rather than 8) days of placebo specified at end of triple therapy. † “An expert neurologist unaware of study design clinically evaluated patients.” This involved serial within-day and between-day subjective scoring. # Whether intention-to-treat or protocol analysis of proven eradication.