Table 3. Risk of bias summary: each risk of bias item for each included study.

Included study (year)	Random sequence generation	Allocation concealment	Masking of participants or outcome assessors	Incomplete outcome	Selective outcome reporting	Other bias
Chung et al 2017[11]	Low risk	Unclear	Unclear	Low risk	Low risk	Low risk
ACCORDION et al 2016[15]	Low risk	High Risk	Unclear	Low risk	Low risk	Low risk
Keech et al 2007[21]	Low risk	Low risk	Unclear	High Risk	Low risk	Low risk
Gupta et al 2004[22]	High Risk	High Risk	Low risk	Low risk	unclear	Low risk
Sen et al 2002[23]	Low risk	Low risk	Low risk	High Risk	Low risk	Low risk
Chew et al 2010[24]	Low risk	Low risk	Low risk	High Risk	Low risk	Low risk
Massin et al 2014[25]	Low risk	Low risk	Low risk	Low risk	Unclear	Low risk