Child versus adult research: the gap in high-quality study design

The objective of this study was to determine whether there were differences in study design and purpose between published child- and adult-focused clinical research.

We reviewed all articles published in the New England Journal of Medicine, Journal of the American Medical Association, Annals of Internal Medicine, Pediatrics, Archives of Internal Medicine, and Archives of Adolescent and Pediatric Medicine during the first 3 months of 2005 and assessed each study's design and purpose. We compared articles focused on adults with those focused on children.

We included 370 original research reports in our analysis (New England Journal of Medicine, n = 46; Journal of the American Medical Association, n = 60; Annals of Internal Medicine, n = 27; Pediatrics, n = 130; Archives of Internal Medicine, n = 73; Archives of Adolescent and Pediatric Medicine, n = 34), of which 189 included only adults as subjects and 181 only children. Among adult studies, compared with child studies, there were more randomized, controlled trials (23.8% vs 8.8%) and systematic reviews (10.6% vs 1.7%) and fewer cross sectional studies (16.9% vs 40.9%). Study purposes also varied, with studies of therapies constituting 38.1% of adult studies, compared with 17.7% of child studies. In contrast, epidemiological studies, defined as studies describing the prevalence or incidence of diseases or risk factors or showing associations between risk factors and diseases, constituted 6.4% of adult studies, compared with 26.5% of child studies.

In 6 leading generalist and specialist journals, studies involving adults were significantly more likely than child studies to be randomized, controlled trials, systematic reviews, or studies of therapies. If such studies are to be viewed as the highest possible quality of evidence, then this difference has implications for quality of care for children and for funding and future directions in clinical research involving children.