GDM: Postpartum Care (2008)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  • To determine the rate of GDM recurrence in a Japanese population
  • Report risk factors associated with GDM recurrence
Inclusion Criteria:
  • Pregnant women diagnosed with GDM or one abnormal value (OAV) on the 75 g OGTT
  • At least one subsequent pregnancy
Exclusion Criteria:
  • Women with pregestational diabetes
Description of Study Protocol:

Recruitment

Women delivering at term from January 1, 1993 - December 21, 2003 at two health clinics in Japan.

Design

Maternal outcome after delivery of index pregnancy (6 months - 7 years) was followed carefully regarding the recurrence of GDM or the development of DM.  Study included 69 women having diagnosis of GDM (n=32) or OAV (n=37) during their index pregnancy and then had a subsequent pregnancy.

Blinding used (if applicable): Not applicable

Intervention (if applicable): Not applicable

Statistical Analysis

 T-test and logistic regression. p-value <0.05 indicated statistical significance

Data Collection Summary:

Timing of Measurements

  • Women diagnosed with GDM or OAV seen in Japanese clinics over 10 year period were followed through next pregnancy.  Postpartum 75g OGTT performed 1-3 months after delivery and Japan Diabetes Society criteria were used

Dependent Variables

  • Screening for GDM/OAV : Blood glucose measured at random at 7-10 weeks and 24-30 weeks and if glucose >100mg/dL, 75 g OGTT was performed.  GDM and OAV made according to Japanese criteria

Independent Variables

  • maternal age, family history of DM, BMI before pregnancy and at delivery, gestational weight gain, and interval between pregnancies
  • sum of blood glucose at 0, 30, 60, 120 minutes
  • sum of insulin levels (IRI) at  30, 60, 120 minutes
  • insulinogenic index : blood glucose at 30 min-blood glucose at 0 min/ (insulin at 30min - insulin at 0 min )
  • HbA1c

Control Variables

 

Description of Actual Data Sample:

Initial N: 69 (32 GDM, 37 OAV)

Attrition (final N): 2 developed DM in the interval between the index and subsequent pregnancy (67)

Age: Women having GDM during index pregnancy were more likely to have recurrent GDM if they were older (28.8 vs 24.5 years, P=0.03).

Ethnicity: Japanese

Other relevant demographics:

Anthropometrics

Location:

Hachioji Medical Center of Tokyo Medical University and Yoneyama Obsetric Hospital, Japan

Summary of Results:

Maternal demographics in the index pregnancy and their relationship to recurrence of GDM

Recurrent GDM Nonrecurrent GDM OR P-Value
n 21 9
Age (year) 28.8 ± 5.1 24.5 ± 2.3 1.25 0.0254
Parity >1 (%) 76.2 44.4 4 0.0062
Family history (%) 57.1 55.6 0.72 NS
BMI before pregnancy (kg/m2) 20.0 ± 1.9 22.4 ± 1.9 0.24 NS
Gestational age at delivery (weeks) 38.2 ± 2.8 38.9 ± 2.1 1 NS
HbA1c (%) 6.6 ± 0.7 5.8 ± 0.6 2.41 0.014
Birth weight of infant (g) 3244.6 ± 656.2 3086.9 ± 520.3 0.14 NS

Other Findings

  • The recurrence rate from index GDM and index OAV were 65.6% and 40.5%, respectively
  • The development to GDM from the index OAV was more common in women with low ∑IRI (179.0 ± 43.5 versus 244.8 ± 66.6, p = 0.0273; OR 0.14; 95% CI 0.021–0.983).
Author Conclusion:
Study demonstrated that 65.6% of the index pregnancy recurred GDM in the subsequent pregnancy in the Japanese population. The development from the initial OAV to the subsequent GDM was 40.5%. The risk factors of the subsequent GDM were weight gain and interval between pregnancies in both the initial GDM and OAV. Prospective studies regarding reduction of the subsequent GDM by control of body weight and advice on the interval with the next pregnancy are required.
Funding Source:
University/Hospital: Hachioji Medical Center, Tokyo Medical University, yoneyama Obstetrics & Gynecology Hospital
Reviewer Comments:

Percent of eligible women participating was unclear.

Study period over 10 years - secular trends may have contributed to differences between recurrent and non-recurrent GDM.

Only present unadjusted odds ratios rather than using multivariate analyses to examine independent effects of age, bmi, etc

 

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? ???
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? No
  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? 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.) No
  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? No
  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? 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? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? Yes
  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? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  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? N/A
  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