GDM: Pharmacologic Therapy (2008)
Women with singleton pregnancies who had GDM diagnosed between 12 and 34 weeks between January 1999 and December 2002.
Abnormal glucose load test (GLT) of 140 mg/dL or greater and a diagnostic 3-hour glucose tolerance test (GTT) using National Diabetes Data Group (NDDG) criteria (fasting > 105, 1 hour > 190, 2 hours > 165, 3 hours > 145 mg/dL.
Recruitment
Recruited from Kaiser Permanente Northern California Medical Care Program. 2 study groups were identified:
Insulin group (those with GDM diagnosed in 1999-2000)
Glyburide group (those with GDM diagnosed in 2001-2002).
Subgroup of women with GDM diagnosed in 2001-2002 who were treated with insulin not glyburide
Design: Retrospective Cohort Study
Blinding used (if applicable): Not applicable
Intervention (if applicable): Glyburide or insulin therapy
Statistical Analysis
Student t test was used to evaluate the difference of means, Chi squared test or Fisher exact test where appropriate was used to evaluate the difference in proportions, the nonparametric Wilcoxon 2-sample test was used for interval level variables found not to be normally distributed by the Shapiro-Wilks test at p <0.01. Multivariable logistic regression was used to compute the adjusted odds ratios (ORs) and 95% CIs controlling for variables shown to differ between the insulin and glyburide groups in univariate analyses.
Timing of Measurements
All data collected from review of clinical information databases and charts, KPNC database, and KPNC Neonatal Minimum Data Set.
Dependent Variables
- Maternal outcomes of insulin and glyburide groups (Delivery gestational age, method of delivery)
- Neonatal outcomes of insulin and glyburide groups (Birthweight, number of LGA, SGA, macrosomic, NICU admissions)
Independent Variables
- Glyburide therapy
- Insulin therapy
Control Variables
-
BMI
-
Ethnicity
-
Gestational age at diagnosis of GDM
-
Degree of glucose tolerance at diagnosis of GDM
Initial N: 584 women
Attrition (final N): 584
Age: Insulin group 32.1 + 5.2 years, Glyburide group 32.8 + 5.4 years
Ethnicity: (p value 0.001 between groups)
Number (%) | Insulin | Glyburide |
White | 116 (43) | 65 (28) |
Hispanic | 66 (25) | 56 (24) |
Black | 10 (4) | 9 (4) |
Asian | 64 (24) | 88(37) |
Other relevant demographics:
There were signficant differences between groups in fasting oral glucose tolerance tests but no signficant differences between groups in the 1, 2 or 3 hour values.
Anthropometrics
Other than the differences in ethnicity in groups there were no other signficant differences.
Location: Kaiser Permanente Northern California Medical Care Program
Maternal and neonatal characteristics mean + SD |
Insulin group n = 268 |
Glyburide group n = 236 |
P value |
Delivery gestaional age (wk) |
38.8+ 1.7 | 38.7 + 1.7 | 0.61 |
Birthweight (g) |
3599 + 650 |
3661 + 629 |
0.28 |
LGA no (%) |
63 (24) |
60 (25) |
0.62 |
Macrosomia no (%) | 64 (24) | 60 (25) | 0.69 |
Preeclampsia no (%) | 16 (6) | 28 (12) | 0.02 |
Phototherapy no (%) | 12 (5) | 21 (9) | 0.046 |
NICU :admission no (%) | 65 (24) | 35(15) | 0.008 |
NICU: length of stay (d) | 4.3+ 9.6 | 8. 0 + 10.1 | 0.002 |
Other Findings - Comparision of glyburide and insulin groups: adjusted odds ratio for birth outcomes
OR | 95 % CI | |
Preeclampsia | 2.32 | 1.17-4.63 |
Macrosomia | 1.28 | 0.82- 2.00 |
LGA | 1.44 | 0.91-2.27 |
Hyperbilirubinemia | 1.18 | 0.75-1.85 |
NICU admission | 0.57 | 0.34-0.93 |
Phototherapy | 2.20 | 0.99-4.87 |
University/Hospital: | University of Copenhagen (Denmark) |
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? | ??? | |
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? | ??? | |
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? | 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? | Yes | |
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? | Yes | |
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? | 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? | 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 | |