Table 1.

Risk of bias

ref. no.	Random Sequence Generation	Allocation Concealment	Blinding (Study patient)	Blinding (treating physician)	Blinding of clinical outcome	Incomplete outcome data addressed	Free of selective reporting	Free of other bias
13	+	+	+	+	−	−	+	+
14	+	+	−	−	−	−	+	−
15	+	+	+	+	−	−	+	+