Methodological challenges to treatment trials for recurrent abdominal pain in children.

Background: Studies evaluating the efficacy of treatments for recurrent abdominal pain (RAP) in children have used a wide range of methods, causing difficulty in the comparison of results. An expert panel on functional gastrointestinal disorders recently made recommendations regarding the standardization of study methods for childhood RAP, but many of their recommendations remain untested or lack supportive evidence.

Methods: During completion of a pilot study and randomized controlled trial for childhood RAP, baseline data were collected regarding the child and parent reports of abdominal pain frequency and intensity, type of abdominal pain, missed activities due to abdominal pain, psychological factors for the parent and child, parenting styles, and referral source (pediatric gastroenterologist vs general pediatrician).

Results: Children and parent pain reports showed good agreement in children younger than 13 years (weighted kappa, 0.77; 95% confidence interval [CI], 0.71-0.84), but only marginal agreement in children 13 years or older (weighted kappa, 0.37; 95% CI, 0.30-0.45). We found no significant differences in pain characteristics or psychological factors between children referred by pediatric gastroenterologists in a tertiary care center and those referred by community-based primary care pediatricians. However, children with symptoms consistent with nonspecific functional abdominal pain were reported by their parents to have less frequent pain (P=.003) and fewer missed activities (P=.003) than children with symptoms of irritable bowel syndrome or functional dyspepsia.

Conclusions: Subjects referred by gastroenterologists and general pediatricians were similar, but the subtype of functional gastrointestinal disorder might be an important baseline characteristic of subjects in future RAP studies. We suggest that future interventional studies of childhood RAP measure 2 outcomes with pain reports obtained directly from children. Any child with fewer days of pain and missed activities due to pain after therapy would be considered improved, and those with no missed activities and 4 or fewer days of pain per month at follow-up would be considered healed.