Table 2.

Assessment for risk of bias in the randomized clinical trials.

Study	Concealment of Randomization	Patients Blind	Healthcare Providers Blinded	Data Collectors Blinded	Outcome Assessors Blinded	Intention-to-treat analysis
Chen 2010 [21]	Yes	No	No	No	No	Yes
Xi 2015 [22]	Yes	No	No	No	No	Yes
Ai 2013 [23]	Yes	No	No	No	No	Yes
Yu 2015 [24]	Yes	No	No	No	No	Yes
Dou 2016 [25]	NA	No	No	No	No	Yes
Chen 2007 [26]	NA	No	No	No	No	No
Chung 2012 [27]	Yes	Yes	No	NA	NA	Yes
Xu 2013 [28]	Yes	No	No	No	No	NA