Table 2.

Bias matrix among randomized controlled trial studies.

Parameters of bias in RCTs	Kielstein 2004	Abe 2010	Abe 2011	Schwenger 2012	Badawy 2012	Mishra 2017
Sequence generation	L	UC	L	L	UC	H
Allocation concealment	L	UC	UC	UC	UC	UC
Blinding of patients and personnel	L	H	H	H	H	H
Blinding of outcome assessors	L	UC	UC	H	H	H
Incomplete outcome data	L	L	L	L	L	H
Selective outcome reporting	UC	L	L	L	L	H
Other sources of bias	L	UC	UC	UC	UC	UC

L = low risk of bias, H = high risk of bias, RCT = randomized controlled trials, UC = unclear risk of bias.