Empirical evaluation of age groups and age-subgroup analyses in pediatric randomized trials and pediatric meta-analyses.
BACKGROUND
An important step toward improvement of the conduct of pediatric clinical research is the standardization of the ages of children to be included in pediatric trials and the optimal age-subgroups to be analyzed.


METHODS
We set out to evaluate empirically the age ranges of children, and age-subgroup analyses thereof, reported in recent pediatric randomized clinical trials (RCTs) and meta-analyses. First, we screened 24 RCTs published in Pediatrics during the first 6 months of 2011; second, we screened 188 pediatric RCTs published in 2007 in the Cochrane Central Register of Controlled Trials; third, we screened 48 pediatric meta-analyses published in the Cochrane Database of Systematic Reviews in 2011. We extracted information on age ranges and age-subgroups considered and age-subgroup differences reported.


RESULTS
The age range of children in RCTs published in Pediatrics varied from 0.1 to 17.5 years (median age: 5; interquartile range: 1.8-10.2) and only 25% of those presented age-subgroup analyses. Large variability was also detected for age ranges in 188 RCTs from the Cochrane Central Register of Controlled Trials, and only 28 of those analyzed age-subgroups. Moreover, only 11 of 48 meta-analyses had age-subgroup analyses, and in 6 of those, only different studies were included. Furthermore, most of these observed differences were not beyond chance.


CONCLUSIONS
We observed large variability in the age ranges and age-subgroups of children included in recent pediatric trials and meta-analyses. Despite the limited available data, some age-subgroup differences were noted. The rationale for the selection of particular age-subgroups deserves further study.
Department of Pediatrics, Division of Infectious Diseases, Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California 94305, USA. dcontop@stanford.edu
Despina G
DG
Contopoulos-Ioannidis
Iva
I
Seto
Michele P
MP
Hamm
Denise
D
Thomson
Lisa
L
Hartling
John P A
JP
Ioannidis
Sarah
S
Curtis
Evelyn
E
Constantin
Gitanjali
G
Batmanabane
Terry
T
Klassen
Katrina
K
Williams
D000367:Age Factors; D002648:Child; D006801:Humans; D015201:Meta-Analysis as Topic; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D012107:Research Design / Q000592:standards