Table 2.

Quality of the randomized studies.

Study (first author)	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other sources of bias
Uedo et al., 2007	Low	Low	Low	Low	Low	Low	Unclear
Jeong et al., 2007	Low	Low	Low	Unclear	Unclear	Unclear	Unclear
Ohya et al., 2010	Low	Unclear	Unclear	Unclear	Unclear	Low	Unclear
Imaeda et al., 2011	Low	Low	Low	Low	Low	Low	Unclear
Tomita et al., 2012	Low	Unclear	Low	Low	Low	Low	Unclear
Jang et al., 2012 †	Low	Unclear	Unclear	Unclear	Low	Unclear	Unclear
Noh et al., 2013	Low	Unclear	Unclear	Unclear	Low	Unclear	Unclear
Kagawa et al., 2016	Unclear	Unclear	Low	Low	Low	Unclear	Unclear
Yamasaki et al., 2018	Low	Unclear	Unclear	Low	Low	Low	Unclear
Tsuchiya et al., 2017	Low	Low	Low	Unclear	Unclear	Low	Unclear
Hirai et al., 2018	Low	Low	High	High	Unclear	Low	Unclear
Hamada et al., 2018	Low	Low	High	Low	Low	Unclear	Unclear
Ishii et al., 2018	Low	Low	High	Low	Low	Low	Unclear
Horikawa et al., 2018	Low	Unclear	Unclear	Low	Low	Low	Unclear
Komori et al., 2019	Low	Unclear	Unclear	Low	Low	Low	Unclear
Ichida et al., 2018	Low	Low	Low	Low	Low	Unclear	Unclear

^†abstract.