GDM: Monitoring (2008)
- Women diagnosed with GDM according to criteria of Carpenter and Coustan
- Women with pregestational diabetes or fasting glucose levels of 105 mg/dl and above due to initiation of insulin treatment
- Twin pregnancies
Recruitment
Consecutive pregnancies referred to diabetes-in-pregnancy program between May 1999 and April 2000. Women were recruited from 2 different treatment settings but were managed by the same team of health care professionals using a standardized protocol.
Design: Nonrandomized Clinical Trial. Allocation to treatment group was based on treatment setting.
Blinding used (if applicable): not possible
Intervention (if applicable)
- Assigned to 1 hour or 2 hour monitoring groups
- Glucose levels measured fasting, and either 1 hour (1-hour monitoring group target values <140 mg/dl) or 2 hours (2-hour monitoring group target values <120 mg/dl) postprandially
- All women seen by registered dietitian for individualized counseling and instruction
- All women given a memory-based blood glucose meter
- Insulin therapy initiated on individual basis
Statistical Analysis
Statistical analysis performed using Student's t test, chi-square test, and multiple regressions.
Timing of Measurements
Measurements completed during pregnancy.
Dependent Variables
- Perinatal outcomes collected from medical records: gestational week at delivery, fetal weight, weight percentile at delivery, rate of macrosomia (>4000 g) and large for gestational age (LGA > 90th percentile)
Independent Variables
- Glucose levels measured fasting, and either 1 hour (1-hour monitoring group target values <140 mg/dl) or 2 hours (2-hour monitoring group target values <120 mg/dl) postprandially
Control Variables
- Demographic data
Initial N: 122 women with GDM
Attrition (final N): 112 women with GDM, 66 assigned to 1 hour monitoring group, 46 women to 2 hour monitoring group. 4 women excluded for twins, 6 women lost to follow up.
Age: mean age 1-hour monitoring: 30.9 ± 5.44 years, 2-hour monitoring: 33.1 ± 5.24 years
Ethnicity: not mentioned
Other relevant demographics:
Anthropometrics: Women in the 2 hour group were older, but there were no significant differences in parity, family history of diabetes, rate of GDM in previous pregnancies, weight gain, pregestational BMI and 50 g glucose challenge test and 100 g oral glucose challenge test results.
Location: Israel
Neonatal Outcomes by Treatment Group
|
1-hour monitoring group (1 h PPG) |
2-hour monitoring group (2 h PPG) |
P value |
Week at delivery |
39.5 ± 1.7 |
39.1 ± 1.4 | 0.17 |
Fetal weight | 3325 ± 471 | 3309 ± 608 | 0.88 |
Insulin therapy | 40% | 28% | 0.03 |
Macrosomia |
7.5% |
10.6% |
0.08 |
Cesarean section |
24% |
30% |
0.62 |
Other Findings
There was a significant difference in mean blood glucose levels between the 2 groups (108.1 ± 19.2 and 94.9 ± 21.2 mg/dl, 1 and 2 hours respectively, P < 0.0001).
HbA1c levels were similar in the 2 groups.
Perinatal outcomes were defined as gestational week at delivery, fetal weight (3325 ± 471 vs 3309 ± 608 g, respectively) and percentile (47.2 ± 27 vs 49.6 ± 30, respectively) and were similar for both groups.
Insulin therapy was initiated more frequently in 2-hour monitoring group (28 and 40% of women in groups 1 and 2, respectively, P < 0.05).
Rates of macrosomia (7.5 vs 10.6%), large for gestational age (7.4 vs 15.2%) and delivery by Cesarean section (24 vs 30%) were increased in group 2 (2 hour PPG) but these differences did not reach statistical significance.
Neonatal birth weight was significantly correlated with maternal weight gain during pregnancy (P = 0.001) and a family history of diabetes (P = 0.02).
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? | No | |
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.) | 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? | N/A | |
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? | No | |
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? | 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? | Yes | |
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? | No | |
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 | |