CD: Pregnancy Outcomes (2006)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To investigate obstetric risk factors and pregnancy outcome of patients with pre-diagnosed celiac disease.
Inclusion Criteria:
All pregnancies of women with and without known celiac disease, delivered during the years 1988-2002 at the Soroka University Medical Center.
Exclusion Criteria:
None specifically mentioned.
Description of Study Protocol:

Recruitment

All pregnancies during 1988-2002 at Soroka University Medical Center.

Design

Retrospective cohort.

Blinding used (if applicable)

Unknown.

Intervention (if applicable)

Data collected from database and analyzed.

Statistical Analysis

Statistical significance calculated using the chi square test or Fisher's exact test for differences in qualitative variables and the t-test for differences in continuous variables.  A multivariable logistic regression model was constructed in order to find independent risk factors associated with celiac sprue.  Odds ratios and 95% confidence intervals were computed.

Data Collection Summary:

Timing of Measurements

All deliveries occurred between 1988 - 2002.  Data retrospectively reviewed.

Dependent Variables

  • Previous cesarean delivery
  • Recurrent abortions (2 or more consecutive spontaneous abortions)
  • Fertility treatments
  • Hypertensive disorders
  • Gestational and pre-gestational diabetes mellitus
  • Intra-uterine growth restriction (IUGR)
  • Premature rupture of membranes (PROM)
  • Labor induction
  • Placental abruption
  • Placenta previa
  • Meconium-stained amniotic fluid
  • Vacuum extraction
  • Cesarean delivery
  • Post-partum hemorrhage
  • Apgar score at 1 and 5 minutes less than 7
  • Congenital malformations
  • Perinatal mortality

Independent Variables

  • Maternal age
  • Gestational age
  • Parity
  • Gravity
  • Ethnicity
  • Smoking
  • Maternal anemia
  • Maternal obesity
  • Birth weight
  • Neonatal gender

Control Variables

 

Description of Actual Data Sample:

Initial N: 48 deliveries of patients with known celiac disease, 143,663 pregnancies of patients without celiac disease

Attrition (final N):  See above

Age:  Celiac patients:  29.1 +/- 5.1 years, non-celiac:  28.4 +/- 5.9 years 

Ethnicity:  Jewish or Bedouin Arab 

Other relevant demographics:

Anthropometrics:  No statistically significant differences were noted between the groups regarding clinical characteristics such as birth order, maternal or gestational age, birth weight, and neonatal gender.

Location:  Israel 

 

Summary of Results:

 

Celiac Non- Celiac OR 95% CI p
Previous CD 6.3 10.8 0.5 0.2 - 1.8 0.312
Chronic HTN 2.1 1.9 1.1 0.2 - 8.1 0.916
Mild preeclampsia 2.1 3.7 0.6 0.1 - 4.0 0.552
Gestational DM 8.3 5.6 1.5 0.5 - 4.3 0.405
IUGR 6.3 2.1 3.1 1.01 - 10.2 0.042
PROM 2.1 5.9 0.9 0.1 - 2.5 0.261
Labor Induction 29.2 11.9 3.1 1.6 - 0.7 <0.001
Placental Abruption 2.1 0.7 2.8 0.4 - 20.7 0.279
Meconium-stained amniotic fluid 16.7 15.9 1.1 0.5 - 2.3 0.887
Cesarean delivery 12.5 12.7 1.0 0.4 - 2.3 0.972
Perinatal mortality 2.1 1.4 1.5 0.2 - 11.1 0.668

Congenital malformations

4.2 4.0

1.1

0.3 - 4.3

0.940

Other Findings

No statistically significant differences were noted between the groups regarding maternal or perinatal outcomes, including fertility treatments (0% among patients with known celiac vs 2.5% among patients without known celiac sprue; p = 0.267), recurrent abortions (0 vs 5.2%, p = 0.103), perinatal mortality (2.1 vs 1.4%, p = 0.668).

However, higher rates of labor induction (29.2 vs 11.9%, p < 0.001) and IUGR (6.3 vs 2.1%, p = 0.042) were found among patients with celiac disease as compared to patients without known celiac disease.

Using a multivariable logistic regression model, controlling for maternal and gestational age, a near-significant association was noted between IUGR and celiac sprue (p = 0.051).

Author Conclusion:
In conclusion, the course of pregnancy of patients with celiac disease including perinatal outcomes is favorable.  However, higher rates of IUGR were found among these patients.  Careful surveillance should be performed for early detection of IUGR.  The physician should encourage patients with celiac sprue to maintain a gluten-free diet since treatment throughout pregnancy was found to be an important denominator in the prevention of IUGR.  Further, prospective studies should focus on screening for celiac disease among patients presenting with IUGR of an unknown etiology, since suitable gluten-free nutrition might enhance fetal weight gain.
Funding Source:
University/Hospital: Ben Gurion Unversity of the Negev (Be'er-Sheva, Israel)
Reviewer Comments:

No information regarding definition or compliance with gluten-free diet and assumed patients were treated.

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) 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.) ???
  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? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  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? ???
  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.) ???
  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? No
  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? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? ???
  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? 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)? 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