To compare secular trends in the age representation of published randomized controlled trials (RCTs) in specialty journals during a period of 20 years.
A validated electronic search strategy using Ovid MEDLINE was conducted to identify RCTs published in the years 1985 through 2005.
The publications retrieved were subdivided into age-specific groups: adults, children, both adults and children, and studies with no age group identified. Within 31 specialties, we chose up to 5 specialty journals and 5 pediatric specialty journals.
Main Outcome Measure
Number of RCTs targeting children compared with adults over time. Linear trends were identified using regression modeling, and an interaction term was included to compare rates of increase between age groups.
A total of 174 unique journals with 43 326 unique RCTs with age-specific categorization were included. Adult RCTs increased by 90.5 RCTs per year (95% confidence interval [CI], 78-103), which was significantly higher than either pediatric RCTs, which rose by 16.9 RCTs per year (95% CI, 12-22) or RCTs involving both children and adults, which rose by 22.7 RCTs per year (95% CI, 10-35). Twenty four of 31 specialties (77%) demonstrated a greater rise in the number of published RCTs per year involving adults than those enrolling children.
Adult RCT publications are increasing at a faster rate than pediatric RCTs in almost all specialties.