EAL

GDM: Pharmacologic Therapy (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

The purpose of this study was to assess the influence of strict metabolic control in women with insulin-treated gestational diabetes on the risk of large-for-gestational-age (LGA) newborns, the frequency of obstetrical complications and fetal outcome.

Inclusion Criteria:

Normal ultrasound screening in week 21 of gestation
No maternal chronic or infectious diseases
No multiple pregnancy
No pre-existing diabetes mellitus

Exclusion Criteria:

Excluded if not included above.

Description of Study Protocol:

Recruitment Women were recruited from the Department of Obstetrics and Gynecology of the University of Vienna Medical School which is a tertiary care center serving high-risk pregnancies.

Design Prospective Cohort Study. Women were grouped into either control group (no gestational diabetes) or the intervention group (women with gestational diabetes treated with diet and insulin). They were followed through out their pregnancy and delivery.

Blinding used (if applicable): None

Intervention (if applicable)

Insulin therapy and diet to control gestational diabetes

Statistical Analysis

Binomial logistic regression analysis, t-test and chi-squared test were used. All tests were two-tailed and a statistical value of p<0.05 was considered significant.

Data Collection Summary:

Timing of Measurements

Maternal and neonatal data were collected at the time of delivery

Dependent Variables

Birth complications
Fetal outcome

Independent Variables

Insulin therapy providing metabolic control of fasting glucose < 90 mg/dl and 130 mg/dl postprandially

Control Variables

Description of Actual Data Sample:

Initial N: 875 women; 713 control group, 162 women with GDM

Attrition (final N): 875

Age: See table

Ethnicity: not stated

Other relevant demographics: not stated

Anthropometrics: see table

Characteristics	Control group	GDM	P value
Age (years)	30.1 (5.5)	32.9 (5.2)	<0.001
Prepregnancy BMI (kg/m2)	24.3 (5.2)	26.9 (6.2)	<0.001
Gestational age OGTT (weeks)	26.0 (2.9)	25.8 (7.2)	0.63
Fasting value OGTT (mg/dl)	76.5 (7.6)	96.1 (17.1)	<0.001
HbA1c at time of OGTT	4.9 (0.4)	5.4 (0.8)	<0.001
Gestational age at delivery (weeks)	39.0 (1.7)	38.1 (2.2)	<0.001
Birth weight (g)	3471 (512)	3276 (618)	0.02

Location:

Vienna, Austria

Summary of Results:

Variables	Control group	GDM group	p value
LGA newborns (%)	88 (12.3)	27 (16.7)	0.14
Brachial plexus palsy	0	3 (1.8%)	<0.01
Cesarean section (%)	178 (25)	51 (31.5)	0.09
Transfer to NICU (%)	43 (6)	12 (7.4)	0.51

Other Findings

Maternal age, parity, gestational week of delivery, fasting, one- and two-hour glucose concentration of OGTT, HbA1c and BMI were shown not to have influence on LGA of GDM women but BMI was significantly associated with LGA (p=0.02) in the control group.

Author Conclusion:

Strict metabolic control and surveillance in women with insulin-treated GDM seems to attentuate the risk for LGA newborns, diabetic fetopathia, and the influence of maternal BMI on fetal growth.

Funding Source:

University/Hospital:

University of Vienna (Australia)

Reviewer Comments:

Compliance and blood glucose values of GDM group were not reported.

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?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
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.)	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?	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.)	N/A
	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?		???
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	???
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	???
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	???
	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?	N/A
	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?	???
	7.7.	Were the measurements conducted consistently across groups?	N/A
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