Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was performed by using sequential numbers generated at the computer…"
Allocation concealment (selection bias)	Low risk	Quote: "The allocations were contained in opaque, sequentially numbered sealed envelopes"
Blinding of participants and personnel (performance bias)	Low risk	Quote: "The allocations were contained in opaque, sequentially numbered sealed envelopes"
		Comment less likely that participants were aware
Blinding of outcome assessment (detection bias)	Unclear risk	No information was provided on who made the assessment
Incomplete outcome data (attrition bias)	Low risk	Minimal loss to follow up
Selective reporting (reporting bias)	Low risk	Authors seem to report all the outcomes irrespective of their statistical significance
Other bias	Low risk	No other risk of bias was noted