Table 1.

Risk of bias summary. Randomised controlled trials. Cochrane Risk of Bias Tool [44]

	Random sequence generation (selection bias)	Allocation concealment (selection bias)	Blinding participants and personnel for all outcomes (performance bias)	Blinding of outcome assessors for all outcomes	Incomplete outcome data for all outcomes (attrition bias)	Selective outcome reporting (reporting bias)	Other sources of bias
Callahan et al., 2006 [18]	+	+	?	+	+	+	+
Thyrian et al., 2017 [19]	+	-	-	-	-	+	+
Van den Dungen et al., 2016 [15]	+	-	-	?	-	+	+

- High risk of bias, + Low risk of bias, ? Unclear risk of bias