Subgroup analysis
Characteristics of reported subgroup analysis are listed in table 2.
Subgroup analysis were mentioned in the method section for 46.94% (n =
46) trials, 89.90% (n = 88) in the results sections, 56.12% (n=55) in
the discussion section and 26.53% (n = 26) in supplemental appendix.
At least 6 subgroup factors were reported in 63.26 % (n = 62) of
trials. Related the type of subgroup factors 30.61% (n = 30) were
clinical factor and 66.33% (n = 65) were clinical factor plus
biomarkers. More than 6 subgroup analysis were reported in 71.43% (n =
70) of the trials. More than one outcome was reported in 25.51% (n =
25) of trials (mean:1; range:1-3). To show the results of subgroup
analysis forest plots were used in 77.55% (n = 76) of the trials.
For 11.22% (n = 11) of trials, it was unclear whether subgroup analysis
was prespecify or post hoc, in 50% (n = 49) of trials were prespecify
and 31.63% (n = 31) were post hoc.
Only 18.37% (n = 18) use an interaction test to assess heterogeneity of
the treatment effect; a 17.35% (n =17) reported subgroup analysis
without any statistical analysis.