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 evaluate the effectivenes of glyburide in patients with gestational diabetes who failed diet therapy.

Inclusion Criteria:

Women with gestational diabetes
Singleton pregnancy
Beyond the first trimester
Unable to maintain euglycemia with diet alone during July 2001- December 2002.

Exclusion Criteria:

Excluded if not included above.

Description of Study Protocol:

Recruitment

All subjects who met the eligibility criteria were recruited between July 2001 and December 2002.

Design: Prospective Cohort Study

Women with gestational diabetes mellitus who failed euglycemia with diet alone were treated with oral glyburide. Starting dose was 2.5 mg q am before breakfast with an increase in dose to a maximum of 20 mg/day. Goal of treatment was to maintain fasting plasma glucose 90 mg% or less and mean 1 hr postprandial glucose 135 mg % or less. Patients were prescribed an American Diabetes Association diet (30 kcal/kg IBW) and were to monitor blood glucose four times daily. Glucose diaries and adverse drug effects were reviewed weeely.

Blinding used (if applicable)

None

Intervention (if applicable)

Glyburide therapy as an adjunct to diet in the control of gestational diabetes mellitus.

Statistical Analysis

Data were described by means and confidence intervals. P value <0.05 was considered to be significant.

Data Collection Summary:

Timing of Measurements

Measurements on the women were done pre and post delivery.

Dependent Variables

Maternal characteristics
Neonatal characteristics

Independent Variables

Glyburide plus diet therapy
Diet therapy only

Control Variables

Dietary intakes

Description of Actual Data Sample:

Initial N: 73 women on glyburide plus diet therapy, 124 women on diet only

Attrition (final N): same

Age: average 28 (range 18-40)

Ethnicity: see table below

Maternal ethnicity and anthropometrics	Glyburide + diet	Diet only
Caucasian no (%)	43 (59)	70 (59)
African American no (%)	17 (23)	22 (18)
Hispanic no (%)	10 (14)	24 (20)
other no (%)	3 (4)	8 (6)
BMI mean (range)	36 (21-53)	30 (16-54)

Other relevant demographics:

Anthropometrics - see table

Location: University of Florida, Gainesville, FL

Summary of Results:

Other Findings

59 (81%; 95% CI 76.4 - 85.6) had acceptable glucose control on glyburide therapy.

9 women experienced noticable side effects:

Malaise and weakness (4)
nausea (2)
Light headedness (1)
Symptoms of hypoglycemia (2)

11 (19%) had infants with birthweights >4000 grams.

Women in glyburide group were more likely (p<0.05) to be morbidly obese compared to the diet group.

Author Conclusion:

Approximately 80% of patients with gestational diabetes who fail to respond to diet therapy can be treated effectively with glyburide.

Funding Source:

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

Incidence of preeclamsia, neonatal characteristics (jaundice, hypoglycemia, congenital anomalies) weren't evaluated.

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?		???
	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?	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?		???
	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?	Yes
	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?	???
	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?	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?		???
	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?	N/A
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	No
	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?		???
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	No
	8.2.	Were correct statistical tests used and assumptions of test not violated?	???
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	???
	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)?	???
	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