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Methodological issues in randomized trials of pediatric acute diarrhea: evaluating probiotics and the need for standardized definitions and valid outcome measures

  • Author / Creator
    Johnston, Bradley C.
  • BACKGROUND: In a 2006 WHO report, diarrheal diseases ranked second among conditions afflicting children. Pediatric acute diarrhea, although most often the result of a gastrointestinal infection, can also occur as a result of antibiotic exposure. This is often referred to as antibiotic-associated diarrhea (AAD). Previous research suggests that probiotics may be effective in the treatment or prevention of various types of PAD. METHODS: The first study involved a systematic review and meta-analysis of RCTs involving probiotics as an adjunct to antibiotics for preventing AAD in children. The second study was a systematic review of definitions and primary outcome measures employed in RCTs of PAD. The third study used a modified Delphi consensus procedure to develop a new instrument for evaluating the severity of PAD. The study involved steering committee discussions (phase 1) and two electronic surveys (phase 2 and 3) of leading experts in measurement and clinical gastroenterology. RESULTS: The per protocol meta-analysis of ten RCTs significantly favored probiotics to prevent the incidence of diarrhea (NNT = 10). However, this effect did not withstand ITT analysis and among included trials there was considerable inconsistency regarding definitions for the reviews primary outcome measure, the incidence of diarrhea. Study two identified 121 RCTs that reported 62 unique definitions of diarrhea, 64 unique definitions of diarrhea resolution and 62 unique primary outcome measures. Thirty-one trials used grading systems to support outcome evaluation. However, none of the trials (or their citations) reported evidence of their validation. In study three experts agreed on the inclusion of five attributes containing 13 items. Attributes proposed for the IPADDS include: Diarrhea Frequency and Duration, Vomiting Frequency and Duration, Fever, Restrictions in Normal Daily Activities and Dehydration. CONCLUSION: It is premature to draw a valid conclusion about the efficacy of probiotics for pediatric AAD. Definitions of diarrhea and primary outcome measures in RCTs of PAD are heterogeneous and lack evidence of validity. The third study represents content validity evidence for IPADDS. A numerical scoring system needs to be added and further empirical evidence of reliability and validity are required.

  • Subjects / Keywords
  • Graduation date
    2009-11
  • Type of Item
    Thesis
  • Degree
    Doctor of Philosopy
  • DOI
    https://doi.org/10.7939/R3K36F
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Doctoral
  • Department
    • Department of Medicine
  • Supervisor / co-supervisor and their department(s)
    • Vohra, Sunita (Department of Pediatrics & School of Public Health)
    • Tsuyuki, Ross T. (Department of Medicine & School of Public Health)
  • Examining committee members and their departments
    • Fedorak, Richard N. (Department of Medicine)
    • Huynh, Hien Q. (Department of Pediatrics)
    • Rogers, W. Todd (Department of Educational Psychology)
    • McFarland, Lynne V. (Department of Health Services Research and Development)