Methods
A protocol including study selection criteria and data extraction methods was developed. The systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (registration number: CRD42019133104; Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019133104; Registered on 04 September 2019), and was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement 13. Ethical approval was not required for this study. This study did not require any funding.