Table 2.

Quality assessment: risk of bias assessment with Cochrane Risk of Bias tool (low risk of bias, unclear risk of bias, high risk of bias).

Study	Random sequence generation	Allocation concealment	Blinding		Incomplete data		Selective reporting			Other biases
			Patients/personnel	Assessor
Chiauzzi et al [29]	Low	Unclear	Unclear	Low	Low		Unclear		Unclear
Simon et al [35]	Low	Low	Unclear	Low	High		Low		Low
Carpenter et al [28]	Low	Unclear	Unclear	Low	Low		High		Unclear
Krein et al [33]	Low	Low	Low	Low	Low		Low		Low
Irvine et al [32]	Unclear	Unclear	Unclear	Low	Low		High		Unclear
Weymann et al [37]	Low	Low	Low	Low	Low		Low		High