Table 2.

Risk of bias in published randomized control trials

Study	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other bias	Score
Gadallah 1999 [16]	UC	UC	Low risk	Low risk	Low risk (Loss to follow-up: 0)	Low risk	Low risk	5
Wright 1999 [14]	Low risk	Low risk	Low risk	Low risk	Low risk (Loss to follow-up: 0)	Low risk	Low risk	5
Tsimoyiannis 2000 [10]	Low risk	Low risk	Low risk	Low risk	Low risk (Loss to follow-up: 3/50)	Low risk	Low risk	7
Jwo 2010 [12]	UC	UC	Low risk	Low risk	Low risk (Loss to follow-up: 0)	Low risk	Low risk	5
Laanen 2018 [17]	Low risk	Low risk	Low risk	Low risk	Low risk (Loss to follow-up: 5/95)	Low risk	Low risk	7
Qiao 2012 [18]	UC	UC	Low risk	Low risk	Low risk (Loss to follow-up: 6/116)	Low risk	Low risk	5
Qu 2017 [19]	UC	UC	Low risk	Low risk	Low risk (Loss to follow-up: 0)	Low risk	Low risk	5
Xu 2010 [20]	UC	UC	Low risk	Low risk	Low risk (Loss to follow-up: 0)	Low risk	Low risk	5

UC unclear