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Objectives: To conduct a systematic review on five areas of celiac disease (CD):
- Sensitivity and specificity of serological tests.
- Prevalence and incidence of CD
- CD-associated lymphoma.
- Consequences of testing for CD.
- Interventions for the promotion and monitoring of adherence to a gluten-free diet (GFD).
Data Sources: MEDLINE® (1966 to Oct 2003) and EMBASE (1974 to Dec 2003) databases for each of the five objectives and their respective sub-objectives.
Review Methods: For each CD objective, a detailed and standardized data abstraction form was developed. For each objective, data abstraction was conducted by one reviewer and verified by another. The extracted data was further verified by one of the principal investigators. Quality assessments were performed using specific instruments for each of the included study types. Data for the sensitivity and specificity of each serological marker was considered separately, and studies were further divided according to the age group of the study population. Attempts were made to identify, explain, and minimize clinical and statistical heterogeneity in the included studies.
Results and Conclusion: The sensitivity and specificity of EMA and tTG testing are quite high (over 95% sensitivity, and close to 100% specificity). HLA DQ2/DQ8 testing has high sensitivity (in excess of 90%-95%), but poor specificity. Biopsy appears to have high specificity, but poor sensitivity. CD is a common disorder with about 1% prevalence in the general population, but higher in some high-risk groups, such as, type I diabetics, and those with iron-deficiency anemia (IDA) or low bone mineral density (BMD). With a few limitations, there is a strong association between CD and GI lymphoma. The standard incidence ratios (SIR) for lymphoma ranged from 4 to 40, and standard mortality ratios (SMR) ranged from 11 to 70. Several studies suggest that adherence to GFD reduces the risk of lymphoma in CD patients. Testing for CD is beneficial in at-risk and symptomatic patients, since these patients are compliant with a GFD and would be expected to benefit from this intervention. The data is less clear for asymptomatic screen-identified patients, particularly those who have truly silent CD and/or don't have fully-developed villous atrophy. Education of patients and family members about CD and about the intricacies of a GFD, and participation in local celiac societies, has been shown to improve compliance. Although somewhat controversial, biopsy monitoring of adherence to a GFD appears to be important.
Evidence-based Practice Center: University of Ottawa Evidence-based Practice Center
Topic Nominator: National Institute of Health (NIH) Office of Medical Applications of Research, National Institute of Diabetes and Digestive and Kidney Diseases
Current as of June 2004