Table 1.
Methodological quality assessment of the 33 studies included.
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Colours show the risk of bias for each single item; green: absence of bias, red: presence of bias; yellow: at least one reviewer stated that the item could not be determined.
Methodological quality assessment of the 33 studies included.
![]() |
Colours show the risk of bias for each single item; green: absence of bias, red: presence of bias; yellow: at least one reviewer stated that the item could not be determined.