Table 2.

Bias assessment of included trials[9]

Reference	Adequate sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data adressed	Free of selective reporting	Free of other bias
de Mey et al. [15]	Yes	Unclear	Yes	Unclear	Yes	Unclear	No
Schutz et al. [14]	Yes	Unclear	Yes	Unclear	Yes	Unclear	No
Fischer et al. [16]	Yes	Unclear	Yes	Unclear	Yes	Unclear	No
Fischer et al. [16]	Yes	Unclear	Yes	Unclear	Yes	Unclear	No
de Mey et al. [15]	Yes	Unclear	Yes	Unclear	Yes	No	No