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2009 Research Award Recipient

varmaPrinciple Investigator: Miranda van Tilburg, PhD

Assistant Professor of Medicine
University of North Carolina

Dr. Van Tilburg is an assistant professor of medicine at the UNC Center for Functional GI & Motility in the Division of Gastroenterology and Hepatology at the University of North Carolina at Chapel Hill. She received her Master’s degree in Economic Psychology and her PhD in Health Psychology at Tilburg University, The Netherlands. In 2001, she completed a three-year postdoctoral fellowship in Endocrinology and Medical Psychology at Duke University Medical Center. For her work she was awarded the 2007 Pediatric Junior Investigator Award of the International Foundation for Functional Gastrointestinal Disorders (IFFGD) and a 2008 IFFGD Research Grant.


Validation of the Child/Adolescent Rome III Criteria

Background: The absence of a standardized, well-validated measure of constipation severity has been a significant obstacle to research that seeks to assess treatment outcomes for constipation. Although the Rome criteria were the standard basis for identifying constipation, their inability to assess symptom severity hindered their use. The newly revised Rome Ill Constipation Module (RCM) assesses symptom severity and demonstrates excellent test-retest reliability and specificity of diagnostic criteria, but requires further validation testing. We developed the Constipation Severity Instrument (CSI), a reliable and valid sixteen-item measure that assesses constipation severity and identifies constipation subtypes. We propose to strengthen the validity of the RCM and CSI by comprehensively validating both instruments and comparing their ability to assess constipation severity.

Aims: To 1) determine convergent validity of the RCM, 2) establish criterion validity of the RCM and CSI, and 3) assess sensitivity to change validity of the RCM and CSI by using their severity scores to test the efficacy of biofeedback therapy.

Methods: We will assess convergent validity by correlating RCM subgroup and total scores to CSI subscale and total scores. We will establish criterion validity by using multiple regression analysis of RCM and CSI scores as predictor variables for the number of abnormal anorectal physiology test results, will correlate these scores to all testing results, and will determine threshold severity scores. We will determine sensitivity to change validity by using repeated measures analysis to assess the ability of the RCM and CSI scores to change after biofeedback and counseling for pelvic floor dyssynergia patients. Well-validated, standardized instruments of constipation severity will have significant ramifications on constipation assessment and measurement of treatment outcomes. The use of such instruments has the potential to influence health care providers’ perspectives and behaviors, thus producing a significant impact on evaluation, treatment, and perhaps even clinical outcomes.

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