Data Analysis
Stata 15.1 software (network package and the network graphs package) was
used to conduct network meta-analysis. 19,20 A network
diagram with nodes and lines was constructed to represent different
interventions, the size of the nodes represented the number of
populations, and the thickness of lines between the nodes represented
the number of studies included. For the quit smoking rate (dichotomous
variable), the odds ratio (OR) with 95% confidence interval (CI) was
used to estimate the effect size. The network meta-analysis results were
summarized base on all possible pairwise comparisons, including mixed
comparisons (the combined effect of direct and indirect comparisons) and
indirect comparisons.
In addition, a traditional meta-analysis was conducted by RevMan
software, Similarly, OR with 95% CI was used to calculate the effect
size, and the P -value was used to judge whether there was a
statistical difference between interventions. Statistical heterogeneity
was assessed with the Chi-squared and I -squared
(I 2) tests. High heterogeneity in the results
was identified if the tests were statistically significant (p< 0.05) and the I 2 >
50%, in which case a random-effects model was selected. Otherwise, a
fixed-effects model was used.
The smoking cessation effect of different drugs was estimated based on
the surface under the cumulative ranking curve (SUCRA). The value of
SUCRA ranged from 0 to 100%, when the SUCRA value was 100%, it
indicated that the intervention was the most effective, and the smaller
the value, the worse the intervention.