EAL

GDM: Monitoring (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To compare the efficacy of postprandial and preprandial monitoring in achieving glycemic control in women with gestational diabetes.

Inclusion Criteria:

Singleton pregnancy
Women with gestational diabetes and requiring insulin at or before 30 wk. gestation
Criteria for insulin: FBS: >105 mg/dl, Postprandial: >140 mg/dl

Exclusion Criteria:

History of diabetes before pregnancy
Preexisting hypertension, renal disease, or autoimmune disorder

Description of Study Protocol:

Recruitment

Women screened for study inclusion at their initial prenatal visits.

Design: Randomized Controlled Trial.

Women were assigned to 1 of 2 blood glucose monitoring protocols for the duration of their pregnancies:

Preprandial monitoring: daily monitoring of fasting, preprandial and bedtime capillary-blood glucose concentrations
Postprandial monitoring: daily monitoring of blood glucose concentrations before breakfast (fasting) and 1 hour after each meal.

Blinding Used (if applicable): not used

Intervention (if applicable):

Weekly evaluation by perinatal-diabetes team (OB, RD, nurse educator and counselor)
Diet: 30 to 35 kcal/kg IBW; 3 meals + 1 to 3 snacks and 40-45% energy from carbohydrates.
Calorie intake and food choices adjusted weekly according to weight gain and blood glucose values.
Split dose insulin Regular and NPH and adjusted to achieve FBG of 60-90 mg/dl and prepandial values 69-105 mg/dl or postprandial values <140 mg/dl
Insulin dose was 0.7 u/kg body weight in 1^st trimester, 0.8 u/kg body weight in 2^nd trimester and 0.9 u/kg in 3^rd trimester

Statistical Analysis

The Mann-Whitney U test was used for data that were not normally distributed, Student's t test for other continuous data, and the two-tailed Fisher's exact test for categorical data. Relative risks and 95% confidence intervals were calculated.

Data Collection Summary:

Timing of Measurements

Weekly evaluation by perinatal-diabetes team.

Dependent Variables:

Macrosomia
Delivery by C-section
Fetal hypoglycemia

Independent Variables

Preprandial monitoring: daily monitoring of fasting, preprandial and bedtime capillary-blood glucose concentrations
Postprandial monitoring: daily monitoring of blood glucose concentrations before breakfast (fasting) and 1 hour after each meal.

Control Variables

Description of Actual Data Sample:

Initial N: 66 women with gestational diabetes that required insulin <30 wk. gestation

Attrition (final N): 66, 33 in each group

Age: mean age preprandial monitoring: 31 +/- 6 years, mean age postprandial monitoring: 29 +/- 5 years

Ethnicity: preprandial monitoring: 27 Hispanic, 4 White, 2 Black or Asian, postprandial monitoring: 29 Hispanic, 3 White, 1 Black or Asian

Other relevant demographics:

Anthropometrics: Groups were similar in their age, race, ethnic group, and physical characteristics

Location: United States

Summary of Results:

Other Findings

The mean birth weight in the preprandial monitoring group was significantly higher than the postprandial monitoring group (3848+434 vs. 3469+668 g, P<0.01).

The proportion of LGA infants was significantly higher in the preprandial monitoring group (42% vs. 12%, P<0.01).

Significantly more infants in the preprandial monitoring group had hypoglycemia (<30 mg/dl) requiring glucagon or dextrose infusion for treatment during the first 4 days of life (21% vs. 3%, P<0.05).

The change in HgA1c was significantly less in the Preprandial monitoring group (-0.6+1.6 vs. -3.0+2.2, P<0.001).

Infants born of mothers in the preprandial monitoring group were more likely to be delivered by C-section (36% vs. 12%, P<0.04).

Author Conclusion:

Adjustment of insulin therapy in women with gestational diabetes according to the results of postprandial, rather than preprandial blood glucose values improves glycemic control and decreases risk of neonatal hypoglycemia, macrosomia, and delivery by C-section.

Funding Source:

University/Hospital:

Eastern Virginia Medical School, University of Califorinia Irvine, University of Pennsylvania School of Medicine, Long Beach Memorial Medical Center

Reviewer Comments:

Well controlled study.

The majority of the subjects were Hispanic.

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?	Yes
3.	Were study groups comparable?		Yes
	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?	Yes
	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?	N/A
	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?		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?	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