Note from the National Guideline Clearinghouse (NGC): This guideline was developed by the National Collaborating Centre for Nursing and Supportive Care (NCC-NSC) on behalf of the National Institute for Health and Clinical Excellence (NICE). See the "Availability of Companion Documents" field for the full version of this guidance.
Clinical Effectiveness Review Methods
Search Strategy
The search strategies and the databases searched are presented in detail in Appendix B in the full version of the original guideline document (see the "Availability of Companion Documents" field). All searches were carried out on the following core databases: Medline, Embase, Cinahl (all using the OVID interface) and The Cochrane Library. Additional databases were searched for individual reviews where appropriate.
For this guideline, a general set of terms was produced relating to irritable bowel syndrome (IBS). The relevance of the terms diarrhoea and constipation was explored before they were included in the IBS filter. For each review, terms related to the intervention were combined with the set of IBS terms. Where appropriate, study design filters (randomised controlled trial [RCT] and systematic review) were applied. Results were limited to papers published in English where possible. All searches were updated to June 2007.
Hand-searching was not undertaken following NICE advice that exhaustive searching on every guideline review topic is not practical or efficient. Reference lists of articles were checked for studies of potential relevance.
Methods of the Review
Sifting Process
Once the search had been completed, the following sifting process took place:
- 1st sift: one reviewer sifted the title/abstract for articles that potentially met the eligibility criteria
- 2nd sift: full papers were ordered that appeared relevant and eligible or where relevance/eligibility was not clear from the abstract
- 3rd sift: full papers were appraised, generally by one reviewer using an inclusion criteria form, and this was checked where necessary by a second reviewer.
Quality Assessment and Validity
Once individual papers were retrieved, the articles were checked for methodological rigour (using quality checklists appropriate for each study design), applicability to the United Kingdom (UK) and clinical significance. Assessment of study quality concentrated on dimensions of internal validity and external validity. At this stage, some studies were excluded if the interventions were not licensed for use in the UK or they were not regularly used in the UK. Studies in which the interventions were obsolete were also excluded.
Studies for which the methodological quality indicated a high potential for bias were included in the review, but were not included in the analysis.
Cost Effectiveness Review Methods
Objectives of Cost-Effectiveness Review
- To determine the cost-effectiveness of tests to identify alternative diagnoses in patients meeting the diagnostic criteria for IBS who do not have any "red-flag" symptoms.
- To assess the cost-effectiveness of interventions used in the management of IBS.
Search Strategy for Identification of Studies
Searches were performed on the MEDLINE database for objective 1 using the strategy given in appendix B in the full version of the original guideline document. Specific searches were also performed on the National Health Service economic evaluation database (NHS EED) database using the Medical Subject Heading (MeSH) terms for inflammatory bowel disease (exploded to include Crohn's disease and ulcerative colitis), lactose intolerance and coeliac disease. Free-text searching on the NHS EED database was explored but did not yield any further relevant papers.
Searches were performed on the MEDLINE database for objective 2 using the strategy in Appendix B of the full version of the original guideline document. Specific searches were also performed on the NHS EED database using the MeSH term for irritable bowel syndrome which yielded two further papers. Free-text searching on the NHS EED database was explored but did not yield any further relevant papers.