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CD: Quality of Life (2006)


Green PHR, Stavropoulos SN, Panagi SG, Goldstein SL, McMahon DJ, Absan H, Neugut AI.  Characteristics of adult celiac disease in the USA:  results of a national survey.  Am J Gastroenterol 2001; 96(1):126-131. 

PubMed ID: 11197241
Study Design:
Cross-Sectional Study
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To obtain clinical information from a large number of adults with celiac disease, and to determine the impact of the low rate of recognition of celiac disease in the US.
Inclusion Criteria:
Questionnaire distributed by inclusion in a celiac newsletter with nationwide distribution, email to 1500 members of an Internet discussion group, and direct mail to members of celiac support groups in NY, NJ, MI and CA.
Exclusion Criteria:
None specifically mentioned.
Description of Study Protocol:


Questionnaire distributed via celiac newsletter, directly to celiac support groups and through the Internet.


Cross-Sectional Study.

Blinding used (if applicable)

 Not applicable.

Intervention (if applicable)

Questionnaire completed during 1 year period.

Statistical Analysis

 Statistical analyses comparing patients diagnosed at age >60 years to those <60 years were carried out using SAS.  All comparisons were adjusted for gender using Maentel-Haenszel odds ratios or linear regression for discrete or continuous variables, respectively, unless otherwise noted.  For dermatitis herpetiformis, Sjogren's syndrome, thyroid disease, aphthae, and IBS, unconditional logistic regression was used to adjust for age in addition to gender.  For hip fractures, the comparison was restricted to patients of age >60 years at the time of the survey and unconditional logistic regression was used to adjust for age and gender.  Relative risks for small intestinal lymphoma and adenocarcinoma were calculated as ratios of observed over expected cases.  95% confidence limits were calculated assuming a Poisson distribution.

Data Collection Summary:

Timing of Measurements

 Multiple choice questionnaire.  Responses collected between October 1996 and October 1997.

Dependent Variables

  • Prediagnosis data, diagnosis data, patient's perspective on diagnosis and treatment, follow-up management, and patient's rating of his/her quality of life were collected through multiple choice questionnaire.  Questionnaire was initially tested on 15 patients with celiac disease and subsequently modified to ensure question clarity and expand available selection of answers.  Not tested for reliability and validity. 

Independent Variables

  •  Gluten-free diet info collected through questionnaire as above

Control Variables

  • Demographic info collected through questionnaire 
Description of Actual Data Sample:

Initial N: 1612 respondents (65% response rate)

Attrition (final N):  1138 biopsy proven patients used for analysis, male to female ratio 1:2.9

Age:  mean age 53 years (range 18 - 88 years) 

Ethnicity:  not mentioned   

Other relevant demographics:  75% respondents were biopsy proven and this group was the focus of the analysis, since some that were not biopsy-proven were self-diagnosed.

Anthropometrics (e.g., were groups same or different on important measures)

Location:  United States - all but 1 state represented, but 41% were from Northeast US.


Summary of Results:

 For Biopsy Proven Celiacs:

Diagnosis in Childhood


Diarrhea before diagnosis   85%

Relatives with celiac disease


Diagnosis considered prompt 


Consultation of >2 gastroenterologists 27%
Consultation of >4 gastroenterologists 4%
Prior diagnosis of IBS 36%
Diagnosing MD knowledge of diagnosis 20%
Diagnosing MD knowledge of treatment 32%
Diagnosing MD knowledge of follow-up care 49%
Mean duration of symptoms before diagnosis 11 years

 Other Findings

In terms of dietary compliance, 98% claimed compliance all or most of the time (68% all, 30% most).  Intentional dietary lapses occurred mainly when eating out of the home, 26% at restaurants and 21% at parties.

The majority of respondents were diagnosed in their fourth to sixth decades.

Diagnosis was considered prompt by only 52% - 31% had consulted 2 or more gastroenterologists.

Quality of life before diagnosis was rated as bad by 30%, fair by 33%, good by 24% and excellent by 10%.  Improved quality of life after diagnosis was reported by 77%, unchanged by 15% and worse by 8%.  Those diagnosed over 60 years of age also reported improved quality of life. 

5 respondents had small intestinal malignancies accounting for a relative risk of 300 (60 - 876) for the development of lymphoma and 67 (7-240) for adenocarcinoma.


Author Conclusion:
The large group of adult celiac patients in our study provides data as to the clinical spectrum of celiac disease in the US.  The majority of patients presented with diarrhea had a long duration of symptoms and consider their diagnosis delayed.  Celiac disease results in a markedly increased risk for the development of small bowel malignancies.  Because a gluten-free diet may prevent this complication, early diagnosis is important.
Funding Source:
Reviewer Comments:
Questionnaire not tested for validity or reliability although it was pilot tested.  65% response rate, all but 1 state represented.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? ???
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? ???
  2.2. Were criteria applied equally to all study groups? ???
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? ???
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes