MNT: Gastrointestinal Disorders (2015


Mahadev S, Simpson S, Lebwohl B, Lewis SK, Tennyson CA, Green PHR. Is dietitian use associated with celiac disease outcomes? Nutrients, 2013; 5: 1,585-1,594.

PubMed ID: 23676548
Study Design:
Cross-Sectional Study
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To determine if dietitian use was associated with quality of life, symptom severity or gluten-free diet (GFD) adherence in patients with celiac disease.
Inclusion Criteria:
  • 18 years of age or older
  • Diagnosis of biopsy-proven celiac disease
  • Affiliated Celiac Disease Center of Columbia University or celiac support group conferences in Iowa, California and New York
  • Survey complete with gender, age and dietitian use information.
Exclusion Criteria:
  • Less than 18 years of age
  • No diagnosis of celiac disease
  • Incomplete survey.
Description of Study Protocol:


  • Patients affiliated with Columbia University Medical Center, recruited by email and at office visits
  • Recruited at celiac support group conferences in Iowa, California and New York.


  • Adults with celiac disease completed a survey online or on paper between November 2010 and July 2011
  • Prior to distributions, the questionnaire was administered to a group of 10 patients and subsequently modified for clarity
  • The survey consisted of questions on demographics, celiac disease onset, symptoms and dietitian use, along with three validated celiac disease-specfic instruments to assess quality of life [Celiac disease-specific quality of life instrument (CD-QOL)], disease activity (Celiac Symptom Index) and GFD adherence [Celiac Disease Dietary Adherence Test (CDAT)] respectively
  • Patients were asked how many times they had seen a dietitian: Never, once or more than once
  • Patients were excluded from the analysis if they did not have biopsy-proven celiac disease or omitted gender, age or dietitian use.

Blinding Used


Statistical Analysis

  • Univariate analysis used to identify associations between demographics, dietitian use and CD-QOL, CSI and CDAT
  • Chi-square and Fisher exact tests were used to compare proportions of categorical variables
  • Mann-Whitney U-test used to compare continuous variables
  • Logistic regression performed to develop a multi-variate model identifying variables predictive of three outcomes, as determined by validated scores: Poor quality of life, high symptom activity and poor adherence
  • Two-sided P-values of <0.05 were considered significant.
Data Collection Summary:

Timing of Measurements

Survey with all questions and instruments conducted once for each patient.

Dependent Variables

  • Celiac disease onset
  • Symptoms
  • Dietitian use
  • Quality of life measured using the validated celiac disease-specific quality of life instrument (CD-QOL); membership in the lowest quartile of CD-QOL was taken to indicate poorer quality of life
  • Celiac disease-specific symptom severity measured by Celiac symptom index; cutoff score of at least 35 (suggestive of ongoing disease) used to dichotomize patients
  • Adherence to GFD assessed by validated Celiac Disease Dietary Adherence Test (CDAT); scores of at least 13 were taken to be indicative of poor adherence.
Independent Variables

Dietitian use.

Control Variables

Description of Actual Data Sample:

Initial N

413 patients (319 female, 94 male).

Attrition (Final N)

413 patients.


  • 18 to 30 years: 80 patients
  • 31 to 40 years: 67 patients
  • 41 to 50 years: 75 patients
  • 51 to 60 years: 93 patients
  • 61 to 70 years: 67 patients
  • Over 70 years: 31 patients.


Not described.

Other Relevant Demographics

Educational level
  • High school or less: 10% of patients
  • College: 48% of patients
  • Graduate school: 40% of patients.


Mean body mass index: 24.1kg/m2.


United States.

Summary of Results:

Key Findings

Disease characteristics

  • 49% of patients reported atypical symptoms of fatigue, anemia or osteoporosis; 40% reported classical diarrhea-predominant symptoms; 8% reported no symptoms
  • Most patients' symptoms were improved (70%) or somewhat improved (13%) with GFD
  • Median time since diagnosis was five to 10 years
  • Median delay from onset of symptoms to diagnosis was also five to 10 years.
Dietitian use
  • 326 (79%) reported having seen a dietitian, with 161 (39%) only having seen a dietitian once
  • 40% of patients agreed with the statement "It is hard to find a dietitian knowledgeable about GFD."
  • 46% of patients reported gaining weight since starting GFD
  • No significant difference in BMI between patients who had and had not seen a dietitian (24.0 vs. 25.6, P=0.45).
Quality of life, disease activity and dietary adherence
  • Dietitian use was not associated with CD-QOL, CDAT or CSI on univariate analysis
  • Multivariate analysis identified two covariates associated with low CD-QOL, indicative of poor quality of life: A long delay (more than 10 years vs. less than one year) from symptom onset to CD diagnosis (OR, 3.92; 95% CI, 1.45 to 0.63) and underweight vs. normal weight (OR, 3.46; 95% CI, 1.12 to 10.68)
  • Advanced age (over 60) and time since diagnosis (more than 10 years vs. less than one year) were protective for disease activity measured by CSI (OR, 0.35; 95% CI, 0.17 to 0.71 and OR, 0.34; 95% CI, 0.13 to 0.87, respectively)
  • Dietitian use was not associated with CD-QOL, CSI or CDAT scores on multivariate analysis.

Mean Validated Scores and Use of a Dietitian


Not Seen















Multivariate Analysis of Factors Associated with Low Celiac Disease Quality of Life (CD-QOL), High CD Symptom Index (CSI) and High CD Adherence Test (CDAT)



High CSI


OR 95% CI OR 95% CI OR 95% CI
Seen a Dietitian 1.49 0.68-3.24 0.86 0.45-1.63 0.85 0.47-1.55

Advanced Age (>60)


0.26-1.37 0.35 0.17-0.71



Male Gender 1.29 0.61-2.72 1.24 0.58-2.64 0.92 0.48-1.77

College Educated


0.97-13.7 1.33 0.53-3.38



Time Since Diagnosis


0.13-1.1 0.34 0.13-0.87



Delayed Diagnosis 3.92 1.45-10.63 2.08 0.98-4.41 1.05 0.53-2.07
Underweight vs. Normal Weight 3.46 1.12-10.68 2.52 0.79-8.04 1.9 0.66-5.51
Overweight vs. Normal Weight 1.31 0.62-2.75 0.6 0.31-1.16 0.66 0.36-1.21
Obese vs. Normal 0.86 0.33-2.23 0.75 0.32-1.76 0.65 0.29-1.46


Author Conclusion:
  • In this survey of patients with celiac disease, more than 20% of respondents had never seen a dietitian and 39% saw a dietitian only once
  • Dietitian follow-up fell short of published guidelines, which may relate to insurance access issues
  • Dietitian exposure was not associated with symptom severity, adherence or quality of life, while delay of diagnosis was associated with poorer quality of life
  • Further prospective analysis is needed to evaluate the benefits and cost-effectiveness of dietitian referral in the care of patients with celiac disease.
Funding Source:
Other: No funding sources were used
Reviewer Comments:
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) Yes
  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) Yes
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? Yes
  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? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  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? No
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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? Yes
  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.) Yes
  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? N/A
  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? No
  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? No
  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? Yes
  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? Yes
  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? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  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