Statistical analysis
We estimated intervention effects by calculating risk ratios (RR) for
dichotomous outcomes or mean difference (MD) for continuous outcomes,
with a 95% confidence interval (CI). Heterogeneity between studies was
calculated using the I2 statistic in Review
Manager version 5.4.1. The data were considered substantial
heterogeneity if I² was 50% or greater. When clinical and
methodology heterogeneity were considered, subgroup analyses were
conducted by the indications (pain or fever relief), the doses of
treatment, the different types of AEs, and different dosing times,
otherwise meta-analysis was performed using the random-effects model
(20). All tests were 2-tailed and p-values < 0.05 was
considered statistically significant. Descriptive analyses were
conducted if there were insufficient similarity information to pool
data. Sensitivity analysis and funnel plots (if more than 10 studies
were included (21)) were performed to assess the possible bias.