Table 4.

Quality evaluation of randomised controlled trials

Randomised controlled studies
Items	Hellberg [26] (2019)	Liang [27] (2016)	Aoike [28] (2017)	Leehey [29] (2016)	Hiraki [30] (2017)	Leehey [31] (2009)
1	Low	Low	Low	Low	Low	Low
2	Low	High	Unclear	Unclear	Unclear	Unclear
3	Low	High	Unclear	High	High	High
4	Low	Unclear	Unclear	Low	Low	Unclear
5	Low	Low	Low	Low	Low	High
6	Low	Low	Low	Low	Low	Low
7	Low	Low	Low	High	Low	High

Notes. 1 Random sequence generation (selection bias); 2 Allocation concealment (selection bias); 3 Blinding of participants and personnel (performance bias); 4 Blinding of outcome assessment (detection bias); 5 Incomplete outcome data (attrition bias); 6 Selective outcome reporting? (reporting bias) 7 Other bias