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 describe the San Antonio experience in the treatment of glyburide for the treatment of gestational diabetes mellitus (GDM) in day-to-day practice and to attempt to identify predictive factors for failure of glyburide treatment in achieving glycemic ranges.

Inclusion Criteria:

Women with gestational diabetes followed at the University of Texas Health Science Center in San Antonio Texas who were treated with glyburide for any period of time. Must have verified self-monitored blood glucose data and delivery information.

Exclusion Criteria:

Women with pre-existing diabetes who entered prenatal care on glyburide.

Description of Study Protocol:

Recruitment

Retrospective review of medical records.

Design: Retrospective Cohort Study.

Women treated with glyburide were divided into 2 groups: those who successfully achieved glycemic targets for the remainder of the pregnancy and those who failed to achieve adequate control on glyburide and switched to insulin or were delivered.

Blinding used (if applicable): not applicable

Intervention (if applicable): not applicable

Statistical Analysis

Student's t test, Wilcoxon rank-sum test, Chi square analysis and Fisher's exact test were used as appropriate for the comparison between the 2 groups.

Data Collection Summary:

Timing of Measurements

Retrospective review of data.

Dependent Variables

Maternal age
Gestational age at glyburide initiation
Fasting blood glucose on GTT
1, 2, 3 hour values on GTT

Independent Variables

Success in achieving glycemic goals on glyburide therapy
Failure to achieve glycemic goals on glyburide therapy

Control Variables

None

Description of Actual Data Sample:

Initial N: 75 women: 63 (84%) glyburide success; 12 (16%) glyburide failure

Attrition (final N): 75 women

Age: Glyburide success mean age 31.3 +/- 6.1 years; glyburide failure 30.3 +/- 5.0 years

Ethnicity: not stated

Other relevant demographics: none stated

Anthropometrics: No signficant differences between groups in regards to age, number of living children, prior history of GDM, macrosomic neonate in prior pregnancy, prepregnancy BMI or BMI at the time of GDM diagnosis.

Location:

University of Texas Health Science Center, San Antonio Texas

Summary of Results:

	Glyburide success n = 63	Glyburide Failure n=12	Statistical Significance between groups (p value)
Gestational age at glyburide inititation weeks + SD	28. 7+ 5.4	23.3 + 7.0	0.03
Fasting on GTT (mg/dL) Mean + SD	102 + 14	115 + 24	0.02
1 hour value on GTT(mg/dL) Mean + SD	205 + 23	230 + 36	< 0.01
2 hour value on GTT (mg/dL) Mean + SD	169 + 34	204 + 66	< 0.01
3 hour value on GTT (mg/dL) Mean + SD	133 + 33	176+ 65	< 0.01
Birth weight (mean + SD)	3327 + 634	3267 + 815	0.78
Fetal Macrosomia (%)	11.1	8.3	1.0

Other Findings

Only 16.7% of women in the failed glyburide group received maximum doses of glyburide before starting insulin therap

Author Conclusion:

In treatment of GDM, glyburide is successful in achieving good glycemic control in most women. Women with high fasting plasma glucose levels, however, may not respond adequately to glyburide therapy.

Funding Source:

Reviewer Comments:

Ethnicity of groups not identified. Group sample sizes were small and not equally sized - only 12 women not successfully treated with glyburide.

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?	???
	2.3.	Were health, demographics, and other characteristics of subjects described?	???
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
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?	Yes
	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?	???
	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.)	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?	???
	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?		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)?	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?	Yes
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