Table 2. Risk of bias assessment of all included studies.

	Burkus et al.	Coric et al.	Davis et al.	Hisey et al.	Phillips et al.	Sasso et al.	Zhang et al.	Janssen et al.
Adequate randomization	+	+	+	+	+	+	Unclear	+
Allocation concealment	Unclear	Unclear	Unclear	Unclear	Unclear	Unclear	Unclear	+
Blinding of patients	-	-	-	-	-	-	-	-
Blinding of care provider	-	-	-	-	-	-	-	-
Blinding of outcome assessor	-	-	-	-	-	-	-	-
Acceptable drop-out rate	Unclear	+	+	-	+	-	+	-
ITT analysis	-	-	-	-	-	-	+	-
Free of selective reporting	+	+	+	+	+	+	+	+
Similar baseline	+	+	+	+	+	+	+	+
Avoided or similar co-interventions	+	+	+	+	+	+	+	+
Acceptable compliance	+	+	+	+	+	+	+	+
Similar timing	+	+	+	+	+	+	+	+
Total score	6	7	7	6	7	6	7	7