MNT: Gastrointestinal Disorders (2015

- To analyze changes in BMI in individuals after diagnosis of Celiac Disease (CD) with particular attention to the potential effects of Gluten Free Diet (GFD) adherence on weight change
- To compare the BMI distributions at diagnosis and after treatment to regional population data from the 2007 National Health Interview Survey (NHIS).
- CD confirmed by biopsy
- Electronic records in the Celiac Center at Beth Israel Deaconess Medical Center
- Age 18 and older
- Gluten-free diet adherence score by a specialized CD dietitian
- Available BMI measurements on at least two separate hospital visits.
- Under age 18
- No confirmation of CD by biopsy
- Only one BMI measurement available
- No assessment of adherence with a GFD.
Recruitment
Review of medical records of patients with known or suspected CD from The Celiac Center at Beth Israel Deaconess Medical Center.
Design
Retrospective study.
Statistical Analysis
- Performed using SPSS for Windows, Rel. 13.0, 2004
- Change in BMI over time was analyzed using repeated-measures analysis with Greenhouse-Giesser correction, where appropriate
- Study outcomes were assessed using Fisher's Exact test or Chi-square test with Yates correction for discrete variables and Student's T-test, as appropriate.
Timing of Measurements
The mean time between first and last BMI was 39.5 months (range, one to 345 months).
Dependent Variables
- Changes in BMI (body weight in kg divided by height in m2) weight class from initial to follow-up visits:
- Underweight: Less than 18.5
- Normal: 18.5 to 24.9
- Overweight: 25.0 to 29.9
- Obese: 30 or higher.
- GFD adherence was stratified into two groups:
- Scores 1 or 2: Adequate GFD adherence
- Scores 3 to 5: Inadequate GFD adherence.
Independent Variables
GFD adherence was determined based on recorded assessment by an expert Celiac dietitian (or from gastroenterologists' notes and serology results), using a five-point rating system.
- Score of 1 to 2: Excellent or good adherence
- Score of 3 to 4: Poor adherence
- Score of 5: Non-adherence.
Control Variables
Percentage of patients with significant weight change: A change of two or more BMI points carried out a priori.
Initial N
1,018 patients with biopsy-proven celiac disease.Attrition (Final N)
- 679 (66.7%) had documentation of BMI and GFD adherence from at least two separate visits
- 123 (12.1%) patients had only one recorded BMI
- 216 (21.2%) either had no records of BMI or had no assessment of their adherence with a GFD and were not included.
Age
All Excluded Subjects N=339 (% or SD) |
Overall Cohort N=679 (% or SD) |
P-value Between Overall Cohort and Excluded Subjects | |
Age | 51.9 (15.5) | 52.4 (16) | 0.64 |
Ethnicity
All Excluded Subjects
N=339 (% or SD)
|
Overall Cohort
N=679 (% or SD)
|
P-value Between Overall Cohort and Excluded Subjects | |
White (%) | 320 (94) | 645 (95) | 0.66 |
Other relevant demographics
All Excluded Subjects N=339 (% or SD) |
Overall Cohort N=679 (% or SD) |
P-value Between Overall Cohort and Excluded Subjects | ||
Demographics | Male (%) | 92 (27) | 166 (24) | 0.36 |
Female (%) | 247 (73) | 513 (76) | ||
Initial BMI | 24.4 (4.9) | 24.0 (5.1) | 0.42 | |
Follow-up BMI | N/A | 24.6 (5.1) | N/A | |
Presentation | Gastrointestinal symptoms | 209 (62) | 424 (62) | 0.8 |
Extra-intestinal symptoms | 130 (38) | 255 (38) | ||
BMI | Less than 18 (%) | 5 (4.1)* | 46 (6.8) | 0.3 |
18.5 to 24.9 (%) | 72 (58.5)* | 416 (61.3) | 0.6 | |
25 to 29.9 (%) | 28 (22.8)* | 139 (20.5) | 0.5 | |
30 or more (%) | 18 (14.6)* | 78 (11.5) | 0.4 |
Anthropometrics
- Baseline characteristics for included patients and those excluded were similar
- There were more females than males (76% female)
- There were more with gastrointestinal symptoms (diarrhea, bloating, abdominal pain, weight loss, nausea, vomiting, GERD, constipation) in 62% vs. non-gastrointestinal signs and symptoms in 38%.
Location
Beth Israel Deaconess Medical Center, Boston, MA.
All Excluded Subjects, N=339 (% or SD) | Overall Cohort, N=679 (% or SD) | P-value Between Overall Cohort and Excluded Subjects | Good Adherence, N=501 (% or SD) | Poor Adherence, N=178 (% or SD) | P-value Between Good and Poor Adherence Groups | |
Demographics | ||||||
Male (%) | 92 (27) | 166 (24) | 0.36 | 117 (23) | 49 (28) | 0.27 |
Female (%) | 247 (73) | 513 (76) | 384 (77) | 129 (72) | ||
Age | 51.9 (15.5) | 52.4 (16) | 0.64 | 52.2 (16.2) | 53 (15.4) | 0.57 |
White (%) | 320 (94) | 645 (95) | 0.66 | 473 (94) | 172 (97) | 0.3 |
Initial BMI | 24.4 (4.9) | 24.0 (5.1) | 0.42 | 23.6 (4.7) | 25.4 (6.0) | Less than 0.001 |
Follow-up BMI | N/A | 24.6 (5.1) | N/A | 24.3 (4.7) | 25.7 (5.8) | 0.001 |
Presentation | ||||||
Gastrointestinal symptoms | 209 (62) | 424 (62) | 0.8 | 316 (63) | 108 (61) | 0.67 |
Extra-intestinal symptoms | 130 (38) | 255 (38) | 185 (37) | 70 (39) | ||
BMI | ||||||
Less than 18 (%) | 5 (4.1)* | 46 (6.8) | 0.3 | 34 (6.8) | 12 (6.7) | 1.0 |
18.5 to 24.9 (%) | 72 (58.5)* | 416 (61.3) | 0.6 | 321 (64.1) | 95 (53.4) | 0.015 |
25 to 29.9 (%) | 28 (22.8)* | 139 (20.5) | 0.5 | 100 (20.0) | 39 (21.9) | 0.6 |
30 or more (%) | 18 (14.6)* | 78 (11.5) | 0.4 | 46 (9.2) | 32 (18.0) | 0.0025 |
*Available for 123 subjects with only one recorded BMI.
MI Category | Less Than 18.5 | 18.5 to 24.9 | 25 to 29.9 | 30 or More |
Initial BMI (N=679) | 46 (6.8%) | 416 (61.3%) | 139 (20.5%) | 78 (11.5%) |
Follow-up BMI (N=679) | 26 (3.8%) | 390 (57.4%) | 164 (24.2%) | 99 (14.6%) |
P-value | 0.02 | 0.17 | 0.11 | 0.1 |
BMI increase two points or more* | 24/46 (52.2%) | 88/416 (21.2%) | 31/139 (22.3%) | 17/78 (21.8%) |
BMI decrease two points or more* | 1/46 (2.2%) | 20/416 (4.8%) | 25/139 (18.0%) | 18/78 (23.1%) |
BMI change less than two points* | 21/46 (45.6) | 308/416 (74%) | 83/139 (59.7%) | 43/78 (55.1%) |
*A BMI change of two points or greater was considered statistically significant.
Other Findings
- In the poor adherence group, there were significantly fewer normal weight patients (53.4% vs. 64.1%, P=0.015), and significantly more obese patients (18.0% vs. 9.2%, P=0.0025)
- In comparison to the regional population of the Northeast United States, obtained from NHIS 2007 data, significant differences were seen at all BMI categories:
- The celiac population was significantly more likely to be underweight (6.8% vs 2.3%, P<0.0001) or normal weight (61.3% vs. 38.9%, P<0.0001) and significantly less likely to be overweight (20.5% vs. 34.8%, P<0.0001) or obese (11.5% vs. 24.0%, P<0.0001) compared with population data.
- Individual patients' follow-up BMIs were statistically higher than initial BMIs (mean 24.6 vs. 24.0, P<0.001)
- The drop in the total percent of underweight patients from baseline to follow-up (6.8% to 3.8%) was statistically significant (P=0.02)
- A BMI change of two points or greater is considered significantly significant:
- 52.2% of those who were underweight at diagnosis demonstrated a BMI increase of at least two points
- 21.2% increased their BMI by more than two points, compared to only 4.8% who decreased by more than two BMI points (P=0.0001).
- The poorly adherent group showed an increased tendency towards weight loss compared with those with good adherence (15% vs. 8%, P=0.01).
- The increased baseline prevalence of obesity seen in patients with poor GFD adherence compared with good GFD adherence on initial evaluation (18% vs. 9.2%, P=0.0025) remained highly significant at follow-up (21.9% vs. 12.0%, P=0.0019)
- Sub-group analyses were performed to determine if timing of BMI measurement from the time of diagnosis made a difference in weight category. Increase in weight was directly correlated with increasing time between BMI measurements, suggesting ongoing weight gain in many individuals.
Other: | not described |
- What criteria did the celiac dietitians use to determine adherence score?
- Were food diaries used?
- Were all patients weighed the same (e.g., in light clothing without shoes)?
- Was amount of exercise or physical activity documented?
Quality Criteria Checklist: Primary Research
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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) | 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? | N/A | |
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? | ??? | |
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.) | 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? | 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? | ??? | |
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? | 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? | No | |
6.6. | Were extra or unplanned treatments described? | No | |
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? | No | |
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)? | No | |
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? | ??? | |
10.1. | Were sources of funding and investigators' affiliations described? | No | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |