GDM: Pharmacologic Therapy (2008)

Citation:
 
Study Design:
Class:
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Quality Rating:
Research Purpose:
The purpose of this study was to investigate whether 2-hour postprandial blood glucose levels up to 8.0 mmol/L affect maternal or neonatal outcomes in pregnancies complicated by gestational diabetes mellitus (GDM).
Inclusion Criteria:
Women with GDM who planned and subsequently delivered at Box Hill Hospital.
Exclusion Criteria:
  • Multiple pregnancies
  • Those whose clinical records were not available or were incomplete
Description of Study Protocol:

Recruitment

Women were recruited by their attendance at the Box Hill Hospital.

Design

Retrospective chart review of women with GDM followed at the Box Hill Hospital from 1991-1997 matched by computer for age and country of birth with women without GDM delivering in the same year.

Blinding used (if applicable):  not applicable

Intervention (if applicable)

Women with GDM were given dietary instruction and taught to monitor their blood glucose level at home 2 hours after each mean using glucose meters. Insulin therapy was commenced when records indicated three blood glucose levels in 1 week >8.0 mmol/L.Starting regimen for insulin was a morning dose of 8-12 units of intermediate-acting insulin. To maintain 2-hour post-prandial blood glucose levels <8.0 mmol/L, most women remained on a once-daily regimen of less than 20 units for the duration of their pregnancy. If this regimen failed to achieve the appropriate levels, an evening dose of the same insulin was introduced.

Statistical Analysis

Chi-squared and 2-tailed, correlated t tests were used.

 

Data Collection Summary:

Timing of Measurements

Maternal  measurements were collected at delivery

Neonatal outcomes were observed upon delivery and within the first 24 hours of life

Dependent Variables

  • Maternal characteristics
  • Neonatal outcomes

Independent Variables

  • The effect of GDM and treatment of postprandial blood glucose levels up to 8.0 mmol/L

Control Variables

  • Age 
  • Country of birth of subjects
Description of Actual Data Sample:

Initial N:  394 women with GDM and 394 controls

Attrition (final N):  same as initial N

Age: Not available

Ethnicity: stated mostly European origin

Other relevant demographics:

Anthropometrics: There were no signifcant differences between groups in parity or gravidity

Location: Box Hill Hospital, Melbourne, VIC

Summary of Results:

 

Variables

GDM

Control

P value

Gestation (weeks) Mean (SD)

38.65 (1.56)

 39.11 (1.91) 

 

<0.001

Length of stay (days)Mean (SD)

 4.81 (2.21)

 4.28 (1.90)

 <0.001

Spontaneous labour (no)

 177

 232

 <0.001

Elective caesarean (no) 66 45 <0.05
Emergency caesarean (no) 42 34 ns

Neonatal hypoglycemia(no)

 5  0  <0.025

Other Findings

There were no signficant differences betwwen groups in the neonatal weights, apgar scores, number of macrosomic or large or small for gestational age neonates.

Women with GDM were more likely to be hypertensive than the control group women during their pregnancy (3.6% vs. 1.3%, p<0.05).

Author Conclusion:

Our study suggests that maternal and neonatal outcomes in GDM women are comparable with those of women without GDM when 2-hour post-prandial glucose levels of up to 8 mmol/L are maintained. This is 1.0 mmol/higher than the current Australian Diabetes in Pregnancy Society recommendation.

Funding Source:
Reviewer Comments:
Did not look at maternal weights, weight gain. A little uncertain about the author's conclusion about maternal outcomes based on gestation,  length of stay, hypertension and neonatal hypoglycemic episodes.
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? ???
  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? 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.) 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? ???
  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? 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? 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? Yes
  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? ???
  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? N/A
  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? ???
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)? Yes
  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