Development of a multidimensional measure for recurrent abdominal pain in children: population-based studies in three settings

Objective. Recurrent abdominal pain (RAP) is a common problem in children and adolescents. Evaluation and treatment of children with RAP continue to challenge physicians because of the lack of a psychometrically sound measure for RAP. A major obstacle to progress in research on RAP has been the lack of a biological marker for RAP and the lack of a reliable and valid clinical measure for RAP. The objectives of this study were (1) to develop and test a multidimensional measure for RAP (MM-RAP) in children to serve as a primary outcome measure for clinical trials, (2) to evaluate the reliability of the measure and compare its responses across different populations, and (3) to examine the reliabilities of the measure scales in relation to the demographic variables of the studied population. Methods. We conducted 3 cross-sectional studies. Two studies were clinic-based studies that enrolled children with RAP from 1 pediatric gastroenterology clinic and 6 primary care clinics. The third study was a community-based study in which children from I elementary and 2 middle schools were screened for frequent episodes of abdominal pain. The 3 studies were conducted in Houston, Texas. Inclusion criteria for the clinic-based studies were (1) age of 4 to 18 years; (2) abdominal pain that had persisted for 3 or more months; (3) abdominal pain that was moderate to severe and interfered with some or all regular activities; (4) abdominal pain that may or may not be accompanied by upper-gastrointestinal symptoms; and (5) children were accompanied by a parent or guardian who was capable of giving informed consent, and children over the age of 10 years were capable of giving informed assent. The community-based study used standardized questionnaires that were offered to 1080 children/parents from the 3 participating schools; 700 completed and returned the questionnaires (65% response rate). The questionnaire was designed to elicit data concerning the history of abdominal pain or discomfort. A total of 160 children met Apley's criteria and were classified as having RAP. Inclusion criteria were identical to those criteria for the clinic-based studies. Participating children in the 3 studies received a standardized questionnaire that asked about socioeconomic variables, abdominal pain (intensity; frequency; duration; nature of abdominal pain, if present, and possible relationships with school activities; and other upper gastrointestinal symptoms). We used 4 scales for the MM-RAP: p