EAL

CD: Quality of Life (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To evaluate the effect of a gluten-free diet on the quality of life of patients with screen-detected celiac disease.

Inclusion Criteria:

Celiac disease based on positive testing for endomysial antibodies and confirmed by finding villous atrophy and crypt hyperplasia on small bowel biopsy.

Exclusion Criteria:

Excluded if not mentioned above.

Description of Study Protocol:

Recruitment

Endomysial antibody testing was done on healthy first-degree relatives of patients with known celiac disease. Healthy participants were neighbors of Finnish Celiac Society members.

Design

Prospective study.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable)

Gluten-free diet for 1 year.

Statistical Analysis

Repeated measures ANCOVA to study the significance of possible confounding factors (i.e. age, sex, economic situation, and BMI) on general well-being or gastrointestinal symptoms. We found no evidence for confounding (i.e. crude and adjusted results were nearly identical). Adjusted results are reported.

Data Collection Summary:

Timing of Measurements

Endomysial antibody testing and small bowel biopsy at beginning of study. Gastrointestinal symptoms and quality of life measured before and after 1 year of gluten-free diet. After 1 year, all celiac patients underwent a second small bowel biopsy and were asked to complete a follow-up questionnaire and 4 day food record.

Dependent Variables

Gastrointestinal symptoms measured through Gastrointestinal Symptoms Rating Scale (GSRS)
Quality of life measured with Psychological General Well-Being Questionnaire (PGWB)

Independent Variables

Gluten-free diet. All patients were counseled and prescribed a gluten-free diet. No other counseling or support was provided during the following year. 4-day food record completed at beginning and after 1 year. Dietitian estimated mean gluten intake using UNIDAP computer program. Patients' concept of long-term adherence to diet evaluated using visual analogue scale.

Control Variables

Description of Actual Data Sample:

Initial N: 19 patients with screen-detected celiac disease and 21 consecutive patients with symptom-detected disease. 105 healthy participants without known celiac disease. Approximately half the patients with screen-detected disease and most of the patients with symptom-detected disease as well as healthy participants were women.

Attrition (final N): See above.

Age: All patients similar in age (late 40s).

Ethnicity: Not mentioned.

Other relevant demographics:

Anthropometrics BMI and economic situation did not differ signifcantly between the screen-detected and symptom-detected groups.

Location: Finland

Summary of Results:

Other Findings

At baseline, patients with symptom-detected celiac disease had poorer quality of life and more gastrointestinal symptoms than those with screen-detected celiac disease.

All patients reported compliance with the diet as intermediate or good. No dietary transgressions observed in 4-day food records after 1 year. All mucosal lesions of the small bowel had resolved at the follow-up biopsy.

After 1 year of following the diet, quality of life for patients with screen-detected disease significantly improved. Mean PGWB score increased from 108 (95% CI: 103 to 113) to 114 (95% CI: 110 to 118), P < 0.01. A similar increase was noted in patients with symptom-detected disease. Mean PGWB score increased from 92 (95% CI: 85 to 99) to 103 (95% CI: 97 to 109), P < 0.01).

Gastrointestinal symptoms also improved in patients with screen-detected disease and in patients with symptom-detected disease. For the screen-detected patients, mean GSRS scores decreased from 1.8 (95% CI: 1.5 to 2.1) to 1.4 (95% CI: 1.3 to 1.6), P < 0.01 and for the symptom-detected patients, mean GSRS scores decreased from 2.6 (95% CI: 2.2 to 3.0) to 1.9 (95% CI: 1.7 to 2.2), P < 0.01.

Author Conclusion:

Gluten-free diet was associated with improved psychological well-being and gastrointestinal symptoms for patients with symptom-detected celiac disease and with screen-detected celiac disease. Concerns about the burden of a gluten-free diet, at least over the short term, may be unfounded. In conclusion, celiac disease represents a continuum that varies from absence of symptoms to severe malabsorption that can cause significant harm. Silent celiac disease is common, and the documented prevalence of the disease will increase with the advent of serological screening. Our findings suggest that, at least over the short term, a gluten-free diet is acceptable and may even provide a quality-of-life benefit to patients with screen-detected celiac disease. Concerns about quality of life while adhering to a gluten-free diet may be unfounded. Nonetheless, more evidence about the long-term benefits (and harms) of early diagnosis and treatment of celiac disease is needed before starting population-based screening.

Funding Source:

Government:

Commission of European Communities

Reviewer Comments:

Dietary compliance through 4 day food record and confirmed with repeat biopsy. Findings only apply to 1 year study period - longer periods may have different results.

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?	Yes
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?	Yes
	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?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	N/A
	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?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	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?	Yes
	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