EAL

GDM: Monitoring (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine the gestational ages at which maternal hyperglycemia is most closely related to fetal macrosomia; to determine whether macrosomia is related to elevations of fasting glucose, postprandial glucose, or both; and to assess the relationship of macrosomia to maternal insulin dose and caloric intake.

Inclusion Criteria:

Diagnosis of diabetes mellitus before pregnancy.
Enrollment in the program before 12 wk. gestation
Delivery after 36 wk gestation

Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment

Women were followed in the Diabetes and Pregnancy Program of the UCSF and Children’s Hospital of SF from November 1981 to August 1989.

Design: Cohort Study.

Blinding Used (if applicable): not applicable.

Intervention (if applicable):

All women seen weekly or biweekly in clinic
All women trained in use of portable glucose meter
Instructed to do blood glucose 4 times/day: fasting and 1 hr after the start of each meal.
Diet plan developed for each subject: 25 kcal/kg DBW for the first trimester and 25-35 kcal/kg desirable body weight during the 2^nd and 3^rd trimesters.
Each month an RD reviewed daily food diaries to evaluate average intakes and to modify diet for desired weight gain and to prevent hypoglycemia, hyperglycemia and morning ketonuria.

Statistical Analysis

For analysis, women were divided into 2 groups based on birthweight: those with fetal macrosomia and those without. In the initial univariate analyses, between-group comparisons of continuous variables were made with the Student's t test (two-tailed) and comparisons of categorical variables were made with the chi-square test. Multiple logistic regression was performed because of the strong covariance of glucose values between each time period and the others.

Data Collection Summary:

Timing of Measurements

All women seen weekly or biweekly in the clinic.

Dependent Variables

Fetal macrosomia

Independent Variables

All women trained in use of portable glucose meter
Instructed to do blood glucose 4 times/day: fasting and 1 hr after the start of each meal.
Diet plan developed for each subject: 25 kcal/kg DBW for the first trimester and 25-35 kcal/kg desirable body weight during the 2^nd and 3^rd trimesters.
Each month an RD reviewed daily food diaries to evaluate average intakes and to modify diet for desired weight gain and to prevent hypoglycemia, hyperglycemia and morning ketonuria.

Control Variables

Description of Actual Data Sample:

Initial N: 111 consecutive pregnant women with Class B through RF diabetes were studied longitudinally from 13 to 36 wk. gestation.

Attrition (final N): 111

Age: mean age women with macrosomia: 30.1 +/- 4.8 years, mean age women without macrosomia: 31.0 +/- 5.2 years

Ethnicity: not mentioned

Other relevant demographics:

Anthropometrics:

Location: California

Summary of Results:

Other Findings

Macrosomia defined as >90^th percentile for gestational age based on California norms.

Macrosomia occurred in 32 (29%) of cases.

Macrosomia was associated with higher postprandial glucose levels up to 32 wk gestation and lower insulin doses from 29 to 36 wk gestation.

Using multiple logistic regression, macrosomia was significantly associated with postprandial glucose between 29 and 32 wk gestation.

8.1 + 0.8 mmol (144 mg/dl) in macrosomia group vs. 7.6 + 0.9 mmol (135 mg/dl) in the nonmacrosomia group. P<0.005.

Postprandial glucose values <7.3 mmol (<130 mg/dl) were associated with increased risk for SGA infants (18%) compared with >130 mg/dl (1%).

Author Conclusion:

Because macrosomia was related to postprandial glucose but not fasting glucose, we conclude that postprandial glucose measurement should be a part of routine care for diabetes in pregnancy. A target 1 hour postprandial glucose value of 7.3 mmol (130 mg/dl) may be the level that optimally reduces the incidence of macrosomia without increasing the incidence of SGA infants.

Funding Source:

University/Hospital:

University of California, The Children's Hospital, University of Cincinnati College of Medicine

Reviewer Comments:

Tightly controlled study with early intervention. No significant differences in dietary intake in macrosomic vs nonmacrosmoic infants.

6 SGA infants in moms with postprandial glucose <130 mg/dl

5 LGA infants in moms with postprandial glucose 120-129 mg/dl and 12 LGA infants in moms with postprandial glucose >150 mg/dl.

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.)	???
	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?	Yes
	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?	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?	N/A
	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