Draft Research Plan

Celiac Disease: Screening

August 27, 2014

Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

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*“Asymptomatic” persons are defined as those without known celiac disease and who have not sought evaluation for potential celiac disease; some asymptomatic persons may have mild nonspecific symptoms.

Abbreviations: GI = gastrointestinal; KQ = key question.

Text Description

This figure depicts the analytic framework that outlines the evidence areas covered in the research plan, including populations, screening, treatment, and outcomes. The populations include adults, adolescents, and children who are asymptomatic for celiac disease. "Asymptomatic" persons are defined as those without known celiac disease and who have not sought evaluation for potential celiac disease; some asymptomatic persons may have mild nonspecific symptoms. After screening, an overarching arrow leads to clinical health outcomes to represent the effect of screening on clinical health outcomes. An initial branch in the framework splits patients into those with normal versus abnormal test results after screening, and assesses the harms of screening. A subsequent branch from persons with abnormal test results leads to treatment, and an arrow from treatment assesses resulting harms. Clinical health outcomes include mortality and morbidity, such as cancer incidence, gastrointestinal outcomes, child growth outcomes, and quality of life.

  1. What is the effectiveness of screening for celiac disease versus no screening in asymptomatic adults, adolescents, or children on morbidity, mortality, or quality of life?
  2. What is the effectiveness of targeted screening for celiac disease versus universal screening in asymptomatic adults, adolescents, or children on morbidity, mortality, or quality of life?
  3. What are the harms of screening for celiac disease?
  4. What is the accuracy of screening tests for celiac disease?
  5. Does treatment of screen-detected celiac disease lead to improved morbidity, mortality, or quality of life compared with no treatment?
  6. Does treatment of screen-detected celiac disease lead to improved morbidity, mortality, or quality of life compared with treatment initiated after clinical diagnosis?
  7. What are the harms associated with treatment for celiac disease?

Contextual questions will not be systematically reviewed and are not shown in the Analytic Framework.

  1. What is the prevalence of celiac disease in asymptomatic adolescents and adults in the United States?
  2. What is the natural history of subclinical or silent celiac disease?

The Proposed Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Review. Criteria are overarching as well as specific to each of the key questions (KQs).

  Include Exclude
Populations KQs 1–4: Asymptomatic adults, adolescents, or children age 3 years and older without known celiac disease

KQs 5–7: Adults, adolescents, or children age 3 years and older with celiac disease

 KQs 1–3: Symptomatic persons seeking evaluation for potential celiac disease
Interventions KQs 1–3: Serologic screening (IgA anti-tTG antibody or other commonly used tests)

KQ 4: Serologic screening (IgA anti-tTG antibody or other commonly used tests); questionnaires

KQs 5–7: Gluten-free diet

  
Comparators KQ 1: Screening vs. no screening

KQ 2: Targeted vs. universal screening

KQ 4: Endoscopy with biopsy

KQ 5: Screen-detected treatment vs. no treatment

KQ 6: Screen-detected celiac disease vs. disease detected after clinical diagnosis

  
Outcomes KQs 1, 2, 5, 6: Morbidity (including outcomes related to nutritional deficiencies), gastrointestinal outcomes (diarrhea, cramping, bloating, etc.), cancer incidence, child growth outcomes, infection rates, quality of life, etc.; mortality

KQ 3: Labeling, complications and harms from biopsy, overdiagnosis

KQ 4: Sensitivity, specificity, positive and negative predictive values, areas under the receiver operating curve, other measures of diagnostic test accuracy

KQ 7: Any harms of treatment

 KQs 1, 2, 5, 6: Laboratory values for nutritional or other deficiencies
Settings KQs 1–3: Primary care KQs 1–3: Specialty clinics
Study designs KQs 1–3, 5–7: RCTs, controlled observational studies, and systematic reviews

KQ 4: Studies evaluating diagnostic accuracy of serologic screening or questionnaires compared with intestinal biopsy and systematic reviews

  

Abbreviations: IgA = immunoglobulin A; anti-tTG = anti-tissue transglutaminase; RCTs = randomized, controlled trials; vs = versus.