Received: 4 August 2020
Accepted: 16 September 2020
First Online: 29 September 2020
Ethics approval and consent to participate
: Not required as data were extracted from published studies that are available in the literature.
: Not applicable.
: Livia Puljak and Tina Poklepovic Pericic are volunteer members of Cochrane Croatia; this manuscript has analyzed Cochrane’s risk of bias tool, but this study was not official project of the Cochrane. Livia Puljak is a volunteer Section Editor of the BMC Medical Research Methodology journal; however, she was not involved in any way in handling of this manuscript. Other authors have no competing interests to declare.