CD: Pregnancy Outcomes (2006)
Recruitment
Pregnant women admitted to 14 participating wards (stratified sampling by province) in region of Campania, Italy from November 2001 - January 2002.
Design
Population-based cohort.
Blinding used (if applicable)
Not used - lab tests determined group assignment.
Intervention (if applicable)
Blood samples taken from pregnant women to screen for celiac disease and compare pregnancy outcomes.
Statistical Analysis
Primarily frequency data. Statistical analysis not described.
Timing of Measurements
Blood samples obtained from all subjects and analyzed.
Dependent Variables
- Pregnancy outcomes
Independent Variables
- Antihuman IgA class antitissue transglutaminase (TGASE) antibodies tested with ELISA
- Endomysial antibodies measured through immunofluorescence
- HLA class II haplotypes assessed using Eurospital Eu-DQ kit
- For known celiacs, gluten-free diet was not defined
Control Variables
Initial N: 5345 women were admitted and 5055 were enrolled (95%), representing 20% of the total births expected in the region over this time period.
Attrition (final N): 5055 women
Age: Undiagnosed celiacs: 29 +/- 3 years, known celiacs: 28 +/- 2 years, non-celiacs: 27 +/- 5 years
Ethnicity: Not mentioned
Other relevant demographics: Not mentioned.
Anthropometrics:
Location: Italy
| Variable | Undiagnosed Celiacs (n=51) | Known Celiacs (n=12) | Non-Celiacs (n=4997) |
| Age (years) | 29 +/- 3 | 28 +/- 2 | 27 +/- 5 |
|
Duration of pregnancy (weeks) |
39 |
40 |
38 |
| First pregnancy (n, %) | 39 (76%) | 6 (50%) | 2798 (56%) |
| Spontaneous abortion (n, %) | 6 (11.7%) | 2 (16%) | 390 (7.8%) |
| Anemia (n, %) | 18 (35%) | 4 (33%) | 564 (13.7%) |
| Vaginal delivery (n, %) | 29 (57%) | 5 (42%) | 2334 (46.7%) |
| Cesarean section (n, %) | 22 (43%) | 3 (25%) | 2189 (43.8%) |
| IUGR (n, %) | 4 (7.8%) | 0 | 251 (5.04%) |
|
Birth weight (g) |
2800 +/- 517 |
3500 +/- 413 |
3220 +/- 550 |
Other Findings
51 of 5055 patients had confirmed positive results. 12 women with known celiac disease were added, resulting in prevalence rate of 1:80.
For known celiacs on a gluten-free diet, TGASE values were negative.
Comparing the 51 TGASE positive with 4997 negative women, an excess risk of abortion, premature delivery, small birth weight, or intrauterine growth retardation was not observed.
Apart from severe anemia, which was 3 times more frequent in celiac women (chi-square = 26, p = 0.0045 after Bonferroni correction), none of these results were significantly different in the celiac (undiagnosed or known) compared with the non-celiac population.
In the 51 undiagnosed celiacs, there was a trend towards a reduced birth weight and a slightly higher abortion rate but these differences were not significant.
In conclusion, our study does not deny the fact that undiagnosed and untreated disease may be a severe cause of discomfort, anemia, associated diseases, and unfavorable outcome of pregnancy in clinically evident patients. In common with others, we have previously shown that after 1 year on a gluten-free diet, the majority of these women enjoy a successful pregnancy. On the other hand, those cases identified only by screening, which are the majority, do not have major clinical complaints and hence it is expected that they may not manifest overt disease or severe complications in reproductive performance.
| University/Hospital: | University of Naples |
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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) | 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) | 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? | 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? | Yes | |
| 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.) | Yes | |
| 5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | Yes | |
| 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? | ??? | |
| 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? | ??? | |
| 6.4. | Was the amount of exposure and, if relevant, subject/patient compliance measured? | ??? | |
| 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? | ??? | |
| 7.3. | Was the period of follow-up long enough for important outcome(s) to occur? | ??? | |
| 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? | ??? | |
| 8.1. | Were statistical analyses adequately described and the results reported appropriately? | No | |
| 8.2. | Were correct statistical tests used and assumptions of test not violated? | ??? | |
| 8.3. | Were statistics reported with levels of significance and/or confidence intervals? | ??? | |
| 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)? | ??? | |
| 8.6. | Was clinical significance as well as statistical significance reported? | ??? | |
| 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 | |