Development of a Multidimensional Measure for Recurrent Abdominal Pain in Children: Population-Based Studies in Three Settings Hoda M. Malaty, MD, PhD*‡; Suhaib Abudayyeh, MD*‡; Kimberly J. O’Malley, PhD*§; Michael J. Wilsey, MD; Ken Fraley, MS¶; Mark A. Gilger, MD#; David Hollier, PhD**; David Y. Graham, MD*‡ ‡‡; and Linda Rabeneck, MD, MPH§§ ABSTRACT. 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 psycho- metrically 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 evalu- ate the reliability of the measure and compare its re- sponses 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 chil- dren with RAP from 1 pediatric gastroenterology clinic and 6 primary care clinics. The third study was a com- munity-based study in which children from 1 elementary and 2 middle schools were screened for frequent epi- sodes 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 par- ent or guardian who was capable of giving informed consent, and children over the age of 10 years were ca- pable of giving informed assent. The community-based study used standardized questionnaires that were of- fered 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 stud- ies. Participating children in the 3 studies received a standardized questionnaire that asked about socioeco- nomic variables, abdominal pain (intensity; frequency; duration; nature of abdominal pain, if present, and pos- sible relationships with school activities; and other upper gastrointestinal symptoms). We used 4 scales for the MM-RAP: pain intensity scale (3 items), nonpain symp- toms scale (12 items), disability scale (3 items), and sat- isfaction scale (2 items). Age 7 was used as a cutoff point for the analysis as the 7-year-olds have been shown to exhibit more sophisticated knowledge of illness than younger children. Results. A total of 295 children who were aged 4 to 18 years participated in the study: 155 children from the pediatric gastroenterology clinics, 82 from the primary care clinics, and 58 from the schools. The interitem con- sistency (Cronbach’s coefficient ) for the pain intensity items, nonpain symptoms items, disability items, and satisfaction items were 0.75, 0.81, 0.80, and 0.78, respec- tively, demonstrating good reliability of the measure. The internal consistencies of the 4 scales did not signif- icantly differ between younger (<7 years) and older (>7 years) children. There was also no significant variation in the coefficient  of each of the 4 scales in relation to gender or the level of the parent’s education. Reliability was identical for the pain-intensity items (0.74) among children who sought medical attention from primary care or pediatric gastroenterology clinics. The intercorrela- tions of factor scores among the 4 scales showed a strong relationship among the factors but not high enough that correlations would be expected to be measuring the same items. The results of the factor analysis identified 5 com- ponents instead of 4 components representing the 4 scales. The 12 items of the nonpain symptoms scale were classified into 2 components; 1 component included heartburn, burping, passing gas, bloating, problem with ingestion of milk, bad breath, and sour taste (nonpain symptoms I), and the other included nausea/vomiting, diarrhea, and constipation (nonpain symptoms II). The program ordered the 5 components on the basis of the percentage of the total variance explained by each com- ponent and consequently by the strength of each compo- nents in the following order: nonpain symptoms I, pain intensity, pain disability, satisfaction, and nonpain symptoms II. Of the 20 items that composed the MM- RAP, 17 met the inclusion criteria of having a correlation of >0.40 on the primary factor analyses. The 3 items that assessed pain intensity met the inclusion criteria as well as the 2 items that assessed satisfaction. Two of the 3 items that assessed disability met the inclusion criteria; however, the missed school item did not. The sleep prob- lem and the loss of appetite items in the nonpain items From the *Department of Medicine, ‡Veterans Affairs Medical Center, ¶Children Nutrition Research Center, #Department of Pediatrics, and ‡‡Division of Molecular Virology, Baylor College of Medicine, Houston, Texas; §Pearson Educational Measurement, Austin, Texas; Department of Pediatrics, School of Medicine, University of South Florida, Tampa, Florida; **Houston Independent School District, Houston, Texas; and §§Sunnybrook and Women’s College Health Sciences Center, University of Toronto, To- ronto, Ontario, Canada. Accepted for publication Oct 14, 2004. doi:10.1542/peds.2004-1412 No conflict of interest declared. Dr Hollier’s current affiliation is: Stephen F. Austin State University, Na- cogdoches, Texas. Reprint requests to (H.M.M.) Veterans Affairs Medical Center (111D), 2002 Holcombe Blvd, Houston, TX 77030. E-mail: hmalaty@bcm.tmc.edu PEDIATRICS (ISSN 0031 4005). 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