EAL

GDM: Monitoring (2008)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To find whether foetomaternal outcomes can be correlated with the degree of glycaemic control, with exercise, diet and/or insulin therapy, towards the terminal phase of pregnancy and if there is any increased risk associated with higher dosage of insulin.

Inclusion Criteria:

GDM cases were selected on the basis of Carpenter and Coustan's modification of O'Sullivan-Mahan's criteria
Pregestational diabetes mellitus cases were those having definite history of prepregnancy hyperglycemia documented by previous blood sugar reports and showing fasting plasma glucose level > 126 mg/dl in any trimester

Exclusion Criteria:

Clinical vasculopathy
Neuropathy
Retinopathy
More than 2+ proteinuria

Description of Study Protocol:

Recruitment

Cases with pregnancy and diabetes mellitus were selected from those attending the antenatal clinic of the department of gynecology and obstetrics at NRS Medical College and Hospital between April 1999 and March 2003.

Design: Prospective Cohort

Blinding used (if applicable): Not applicable

Intervention (if applicable):

All patients were put on diet and light exercise for 2 weeks, then fasting plasma glucose and 2 hour postprandial plasma glucose were estimated
Patients showing fasting plasma glucose > 95 mg/dl and/or postprandial plasma glucose > 120 mg/dl were subjected to insulin therapy
Cases not requiring insulin were followed up weekly
In all cases, HbA1c was estimated in the third trimester to assess glycemic control

Statistical Analysis

Statistical analysis was done by standard error of difference between 2 means and standard error of difference between proportions. P value of <0.05 was considered significant.

Data Collection Summary:

Timing of Measurements

Patients were advised to attend the antenatal clinic every 4 weeks up to 28 weeks of pregnancy. Then every 2 weeks up to 36 weeks and weekly thereafter. They were also advised to attend the diabetes clinic weekly for plasma glucose estimation and insulin adjustment accordingly.

Dependent Variables

During each antenatal visit, body weight, blood pressure, and urinalysis were measured
Plasma glucose of venous blood estimated using enzymatic method
HbA1c measured by HPLC
Maternal outcomes: lower segment cesarean section, pregnancy-induced hypertension, preterm labor, wound sepsis, and postpartum hemorrhage
Fetal complication parameters: large for date (>90th percentile for gestational age), small for date (<10th percentile for gestational age), birth asphyxia (Apgar score <6), congenital abnormalities, perinatal death and metabolic disorders (hypoglycemia, hypocalcemia)

Independent Variables

GDM or pregestational diabetes mellitus

Control Variables

Description of Actual Data Sample:

Initial N: 286 consecutive cases were collected by screening. 27 were lost to follow-up, and 19 were excluded.

Attrition (final N): 240 patients of pregnancy with diabetes mellitus; 176 had GDM and 64 had pregestational GDM

Age: Mean age GDM: 29.48 ± 4.23 years, mean age pre-GDM group: 28.18 ± 5.5 years

Ethnicity: not mentioned

Other relevant demographics:

Anthropometrics: GDM and pre-GDM groups were matched for the risk factors of age > 30 years, BMI > 30, past history of macrosomia, perinatal death, family history of diabetes mellitus, hypothyroidism and unbooked status.

Location: Kolkata, India

Summary of Results:

Maternal and Foetal Complications in Patients Requiring <15 Units and >15 Units of Insulin for Control

Groupwise Insulin Requirement	Number of Cases	Maternal Complications	Foetal Complications
GDM: <15 units	40	100%	27.3%
GDM: > 15 units	88	93.3% (P = NS)	40% (P = NS)
Pre-GDM: < 15 units	0	0	0
Pre-GDM: > 15 units	24	66.7% (P < 0.05)	62.5% (P < 0.05)

Other Findings

Insulin requirement of pregestational diabetes mellitus group was 1.8 times higher than the GDM group (23.61 units vs 41.83 units).

There was no insulin-related increased complications in either group.

The foetal complications were higher in pregestational diabetes (62.5%) than in the GDM group (27.3 and 40% in < 15 units or > 15 units insulin requirement respectively, P < 0.01).

The terminal glycemic parameters (fasting plasma glucose, 2 hours postprandial plasma glucose, HbA1c%) were not different in case of GDM between those with and without foetal complications, except for fasting plasma glucose where "with complications" fasting plasma glucose was lower than without (79.4 ± 13.14 vs 75.28 ± 3.68 mg/dl).

For pregestational diabetes mellitus patients those without complications had a significantly lower level of all of the parameters (fasting plasma glucose 69.75 ± 0.5 versus 122 ± 14.14 mg/dl, postprandial plasma glucose 95 ± 7.4 vs 131.5 ± 12.02 mg/dl, HbA1c 6.8 ± 0.28 vs 7.3 ± 3.6%) compared with those having complications.

Maternal complications could not be segregated as all the subgroups had a very high incidence of cesarean section (60% - 100%).

However, when lower segment cesarean section was excluded and maternal complications segregated, for GDM patients, only fasting plasma glucose was significantly lower in cases without complications while in pregestational diabetes mellitus patients the fasting plasma glucose as well as HbA1c were significantly lower in cases without complications.

Author Conclusion:

Average insulin requirement for normoglycemia for the pre-GDM patients was nearly double to that of GDM patients. The assessment of at term of 3rd trimester glycemic control parameters may not reflect pregnancy outcome for GDM patients and tight control at this stage only may not be of any significant benefit. For pre-GDM patients this is an effective method of outcome assessment for both the mother and fetus, and tight control is advised. The quantity of insulin does not affect outcomes adversely. There is a lack of appropriate sensitization, about the management of diabetic pregnancies, of the obstetricians which can be dealt with and this might allay undue apprehension on their part which can lead to a reduction of very high incidence of cesarean section.

Funding Source:

Reviewer Comments:

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.)	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?	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?	N/A
	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?	Yes
	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?	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)?	N/A
	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?		???
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	No
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