Data analysis
This meta-analysis was performed using Stata, release 14. All results
were binary variables and were presented as summary risk ratios (RR)
with 95% confidence intervals (CI). We calculated the summary RR and
95% CI by using a fixed effects model. A random effects model was used
if the high
heterogeneity19. The
subgroup analysis was conducted according to study type (IST-DP,
IPT-DP-4-6w, IPT-DP-8w, IPT-SP-4-6w, IPT-SP-8w).
The influence of study quality on results was assessed by sensitivity
analysis. The extent of heterogeneity was interpreted by the total
percentage of variation between the studies concerned, measured by theI 2 statistic. The I ² value was
categorized as low if I ² was 0–25%, moderate if I ²was
25–50%, high if I ² was 50–90%. Additionally, Q-statistic was
used to assess the presence of heterogeneity. PQ statistic≥0.05 was
considered to indicate no significant heterogeneity among the included
studies20.
The test of publication bias was not necessary because the included
studies were less
ten21.