Table 2

Methodological quality assessment and risk-of-bias

	Randomisation adequate?	Allocation concealed?	Groups similar at baseline?	Patient blinded?	Care provider blinded?	Outcome ssessor blinded?	Dropout rate described and acceptable?	Intention to treat analysis?	Co-interventions avoided or similar?	Compliance acceptable?	Timing outcome assessment similar?	Report free of selective outcome reporting	Total
Wilkens et al30	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	12
Tant et al31	Yes	No	Yes	No	No	No	Yes	No	Yes	Unclear	Yes	Yes	6
Leffler et al32	unclear	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	10

Risk-of-bias assessed using criteria from the CBRG.27 Studies rated as having a ‘low risk-of-bias’ when at least 6 of the 12 CBRG criteria have been met and it has no serious flaws.