**2. Materials and Methods**

#### *2.1. Protocol Registration*

The preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed for this study [31]. This study's protocol was registered with the National Institute for Health Research (CRD42020203560), which serves as a prospective systematic review register. A detailed protocol can be found at https://www.crd.york.ac. uk/PROSPERO/display\_record.php?RecordID=203560 (accessed on 16 February 2021).
