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GDM: Postpartum Care (2008)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To compare the present carbohydrate metabolism status and anthropomorphic characteristics of women diagnosed as suffering from abnormal carbohydrate tolerance during pregnancy eight years previously with those recorded as having normal glucose tolerance.
Inclusion Criteria:
Participation in a randomized study during Jan-Oct 1985.
Exclusion Criteria:
None specified.
Description of Study Protocol:

Recruitment

Women participating in a randomized trial eight years prior were traced for re-assessment eight years later during Jan-Jun 1993.

Design

Glucose tolerance was measured eight years after pregnancy, and women with abnormal glucose tolerance were compared to those having normal glucose tolerance with respect to blood glucose tolerance at pregnancy, BMI at pregnancy and follow-up, family history, blood pressure.

Blinding used (if applicable): Not applicable

Intervention (if applicable): Not applicable

Statistical Analysis

  • chi-squared tests
Data Collection Summary:

Timing of Measurements

Blood glucose and BMI were measured at time of pregnancy and eight years later

Other risk factors (BMI, waist-hip ratio, blood pressure, and family history) were measured eight years after pregnancy.

Dependent Variables

Non-pregnant diagnostic criteria for the 75 g OGTT:

  • Impaired glucose tolerance : 2-hour glucose value of 7.8-11.0  mmol/l
  • Diabetes mellitus:2-hour glucose value of 7.8-11.0 and >11.0 mmol/l 
  • Any 2-hour post-glucose load value >7.8 mmmol/l being considered abnormal glucose tolerance.

Independent Variables

Pregnant diagnostic criteria for the 75 g OGTT: 

  • normal glucose tolerance [NGT: 2-hour value <7.8 mmol/l]
  • borderline tolerance [borderline GIGT: 2-hour value 7.8-8.5 mmol/l]
  • impaired tolerance [GIGT: 2-hour value 8.6-11.0 mmol/l]

BMI (normal <25, overweight 25-29, obese >30), waist-hip ratio, blood pressure (normo/hyper (>160/90mmHg), and maternal/paternal/sibling history of abnormal glucose tolerance

Control Variables N/A

Description of Actual Data Sample:

Initial N:269 in original randomized study

Attrition (final N): 56.9% participated in follow-up (116)

Age: mean age was 28.7 ± 5.32 years.

Ethnicity: Maltese

Other relevant demographics: none of the women were treated with insulin during pregnancy

Anthropometrics Women with abnormal glucose tolerance had a higher waist-hip ratio (p=.0364) and were more likely to be overweight/obese (p=0.0344)

Location: St Lukes Hospital, Malta

 

Summary of Results:

 

Present Risk factors
Present Characteristics BMI Present Metabolic Status
Normal Tolerance2hr value <7.8 mmol/l Abnormal Tolerance2hr value >7.8 mmol/l % abnormal glucose tolerance Significance
Normal: <25 35 5 12.5  
Overweight: 25-29 37 5 11.9  
Obese: >30 21 13 38.2 p = 0.0344
Waist-Hip ratio        
0.69-0.81 51 7 10.5  
0.82-0.85 24 6 20.0  
0.86-0.94 16 10 38.5 p = 0.0364
Blood Pressure        
Normotensive 87 17 16.4  
Hypertensive>160/90 6 6 50.0 p = 0.0188

Other Findings

  • The prevalence of abnormal glucose tolerance was significantly higher in women who had been noted to have carbohydrate intolerance during their pregnancy (p<0.0001), the prevalence depending on the gestational severity.  
  • Obesity during pregnancy as determined by BMI did not appear to have any statistical risk for the development of subsequent glucose intolerance: prevalence of follow-up abnormal glucose tolerance was 17.0% in women whose gestational BMI was within the normal range and 22.2% in women whose gestational BMI was in the overweight-obese range (p = 0.6415)
  • Family history was associated with an increased risk of developing abnormal glucose tolerance: statistically significant with a maternal (p = 0.0018) or sibling (p = 0.041) family history. A paternal family history showed no increased risks (p = 0.7967).
Author Conclusion:
The present study confirmed that mild forms of carbohydrate intolerance during pregnancy appear to be definite risk factors for the development of carbohydrate metabolism problems later on in life, this being related to the severity during pregnancy and the development of obesity.
Funding Source:
University/Hospital: St. Luke Teaching Hospital
Reviewer Comments:

Eligibility criteria not well defined and authors state " there appeared to be a bias towards those women who had some form of abnormality during pregnancy" but don't describe further

No description of original RCT to know what interventions ppt received

Unclear if groups similar in age; all analyses were unadjusted, so it is unclear what the independent roles of previous blood glucose, current BMI, blood pressure, and family history are in influencing risk

 

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) N/A
  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? N/A
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? No
  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? ???
  2.2. Were criteria applied equally to all study groups? ???
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? ???
  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? ???
  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? No
  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? ???
  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? ???
  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? No
  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? 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? No
  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? No
  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? No
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? No
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? ???
  10.2. Was the study free from apparent conflict of interest? Yes