2.5 Data analysis
Stata 15.0 was applied to conduct meta-analysis, and the research
results are presented as forest plots with 95% confidence intervals.
The combined correlation between the rate of hearing recovery and
incidence of vertigo was assessed by means of the Mantel–Haenszel
method as dichotomous data, combined with the estimation of the ratio of
the two groups of patients. The data from all the eligible studies in
this research were quantitatively combined. The studies’ statistical
variability was analyzed by the P value (P ≤ .05 implying obvious
heterogeneity) and the I2 statistic as a derived Cochran Q statistic
(≥50%, high level of heterogeneity; 25% to <50%, moderate
level of heterogeneity; and <25% means slight level of
heterogeneity). When I2 < 50% and/or P ≤0.05, a fixed-effects
model was applied; otherwise, a random-effects model was applied. The
funnel plots, which do not have sufficient power with fewer than 10
researches involved, were applied to visually evaluate the publication
bias and potential asymmetry.[9]