Fig. 1.

PRISMA Diagram—Identification of studies via databases and registers.

A path diagram describing the review’s process for identifying studies. The process follows 3 phases (identification, screening and inclusion) and involves 5 stages. On the left side, the following stages are described: number of record identification in databases, number of records screened, number of records sought for retrieval, number of reports assessed for eligibility, and finally, number of studies included in the review. Each of the initial 4 stages on the left side has a corresponding stage on the right side where numbers and reasons of removal or exclusion are detailed