Figure 2
The P R I S M A flow diagram shows four section headings arranged vertically on the left side: “Identification”, “Screening”, “Eligibility”, and “Included”. The flowchart is divided into two columns. The left column contains six text boxes, which are labeled as follows: Text box 1: Studies identified through the database (n equals 384). Text box 2: Studies after duplicate remove (n equals 316). Text box 3: Screen studies (n equals 316). Text box 4: Full text studies considered for eligibility (n equals 105). Text box 5: Eligible studies (n equals 41). Text box 6: Studies included in synthesis (47). The right column contains three text boxes, which are labeled as follows: Text box 7: Exclude studies (n equals 211). Text box 8: Full text studies excluded for reason (n equals 64). Text box 9: Additional papers identified during the revision process (n equals 6). The text boxes 1 and 2 are placed under the heading “Identification”. The text boxes 3 and 7 are placed under the heading “Screening”. The text boxes 4, 5, 8, and 9 are placed under the heading “Eligibility”. The text box 6 is placed under the heading “Included”. Text box 1 is connected to text box 2 with a downward arrow. Text box 2 is connected to text box 3 with a downward arrow. Text box 3 is connected to text box 4 with a downward arrow. Text box 4 is connected to text box 5 with a downward arrow. Text box 5 is connected to text box 6 with a downward arrow. Text box 3 is connected to text box 7 with a rightward arrow. Text box 4 is connected to text box 8 with a rightward arrow. Text box 5 is connected to text box 9 with a rightward arrow.A PRISMA flowchart for the literature screening process