Publication bias will be assessed by using Begg's funnel plot and Egger's test. Begg's funnel plots are scatter plots of the log odds ratios (ORs) of individual studies on the x-axis against 1/standard error (SE) of each study on the y-axis. Egger's test is a test for linear regression of the normalized effect estimate (log OR/SE) against its precision (1/SE). An asymmetrical funnel plot or a P-value of < .10 on Egger's test will be considered to indicate the presence of publication bias. If publication bias is detected, trim and fill analysis will be performed. All statistical analyses will be performed using Stata SE version 15.0 (StataCorp, College Station, TX).