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GDM: Medical Nutrition Therapy (2008)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To compare practice patterns of the American College of Obstetrician and Gynecologists (ACOG) Fellows for the diagnosis and treatment of gestational diabetes mellitus (GDM) and type 1 diabetes mellitus with current ACOG recommendations and prior published series.
Inclusion Criteria:
  • practicing ACOG Fellows and Junior Fellows
  • no previous participation in a Network study
Exclusion Criteria:
Did not treat pregnant patients.
Description of Study Protocol:

Recruitment

Surveys mailed to 1,398 ACOG Fellows and Junior Fellows

  • 398 from the Collaborative Ambulatory Research Network - practicing obstetrician–gynecologists who voluntarily participate in survey studies.
  • 1,000 non-Network Fellows randomly chosen by computer from ACOG practicing obstetrics and/or gynecology and have not been previously selected as a part of a Network study.

Design

  • Surveys mailed to 1398 fellows
  • Second mailing to non-network fellows who failed to respond after 6 weeks
  • Compared characteristics of respondents and nonrespondents, practice patterns compared to current ACOG recommendations and previous practice patterns measured in 1987 and 1996.

Blinding used (if applicable):  Not applicable

Intervention (if applicable):  Not applicable

Statistical Analysis

  • Descriptive statistics (mean ± standard error of the mean).
  • Two-tailed t tests - compare group means of age.
  • Analysis of covariance  - Group differences of continuous measures, with Network status and sex as categorical variables and age as the covariate.
  • Chi-squared - Differences in categorical measures 
  • Spearman Correlations among ordinal measures 
  •  All analyses were tested for significance by using {alpha} < .05 
Data Collection Summary:

Timing of Measurements Most recent survey conducted in 2003; two previous surveys in 1987 and 1996 conducted using similar methodology

Dependent Variables

  • Physician and patient demographics (age, sex) 
  • Clinical practice, including screening and diagnostic methods; treatment of diabetes mellitus during pregnancy
  • Physician self-assessment of medical training
  • Network status

Independent Variables

Control Variables

Description of Actual Data Sample:

Initial N: 1398 surveys mailed (398 network physicians)

Attrition (final N): Network 62.5% and non-network 32.4%.  After excluding respondents that did not treat pregnant women, there were 441 surveys (202 network, 239 out of network)

Age: 47.3 +/- 0.4 years for all 569 responders

Ethnicity: not specified

Other relevant demographics: Of all 569 responders, 56.9% male

Anthropometrics:

Location: US- respondents came from all 10 ACOG districts across all 50 states and from the District of Columbia

 

Summary of Results:

 

 Other Findings

No significant difference between sex or age distribution comparing responders with non-responders

Those who treat pregnant patients were on average younger than those who did not and men were less likely to treat pregnant patients than women p=0.01

39.7% (167 of 441) used more sensitive Carpenter and Coustan criteria recommended by the American Diabetes Association whereas 59% (260 of 441) used the National Diabetes Data Group for diagnosis

Provision of Medical Nutrition Therapy: registered dietitian used by 68.9% (304 of 441), diabetes nurse educator by 58.3% (257 of 441) , 27.9% (123 of 441) of the obstetrician–gynecologists performed the medical nutrition therapy education themselves.

Exercise recommended by 73.9% (325 of 441) of respondents.

If medication needed for control of blood glucose, 82.3% (363 of 441) used insulin first, whereas 13.2% (58 of 441) begin with glyburide.

Among those who recommend self-monitoring of blood glucose, 90.7% (400 of 441) prescribe measuring fasting glucose level, 61.2% (270 of 441) recommend 2-hour postprandial tests. Four tests per day are ordered by 63% (278 of 441) of obstetrician–gynecologists, and 12.6% (33 of 416) ask that 5–8 tests be performed daily. The targets for blood glucose results were fasting mean 97.3 mg/dL, standard deviation (SD) 3.2 (n = 409); preprandial mean 103.6 mg/dL, SD 12.4 (n = 124); 1-hour postprandial mean 134.6 mg/dL, SD 15.5 (n = 219); 2-hour postprandial mean 122.1 mg/dL, SD 11.2 (n = 324).

80.3% (354 of 441) use antepartum fetal monitoring in patients with GDM:

  • 74.1 (327 of 441)% used Nonstress test
  • 24.5 (108 of 441) % used biophysical profile
  • 10 (44 of 441)% used amniotic fluid index
  • 7.3 (32 of 441)% used ultrasound assessment of fetal growth 

Fetal monitoring initiated at an average of 35.7 (range 26–41) weeks of gestation for diet-controlled patients and at 32.2 (range 29–39) weeks of gestation for patients on insulin or glyburide.

49.9 (220 of 441)% of participants considered their training during residency regarding GDM to have been comprehensive, and a further 41% (182 of 441) considered it adequate.

Type 1 DM Management

54.9% (242 of 441) of respondents manage glucose control themselves. 

Diabetes specialist, such as an endocrinologist, participates in this care in 34.5% (152 of 441) of patients, a maternal–fetal specialist in 34.5% (152 of 441), a diabetes nurse educator in 16.1% (71 of 441), a registered dietitian in 10.2% (45 of 441), and an office nurse in 5.4% (24 of 441).

90% request a fasting glucose, 56.9% (251 of 441) a 2-hour postprandial value, 31.1% (137 of 441) a 1-hour postprandial test, and 28% (123 of 441) preprandial values, and 6.8% (30 of 441) check random glucose levels.

Author Conclusion:
Practicing obstetrician–gynecologists have incorporated recent recommendations into their practice patterns for both GDM and type 1 diabetes mellitus, including patients’ self-monitoring of blood glucose, exercise, and postpartum testing in GDM.
Funding Source:
Reviewer Comments:

 

  • low response rate (32.4% overall) - concern about external validity
  • looked for differences between network and out-of network providers
  • funded by health resources and services administration - maternal and child health bureau number of males and females slightly discrepant between text and table 1 (324 males in table vs 321 in text )
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) N/A
  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) N/A
 
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? N/A
  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? 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? ???
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) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  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? N/A
  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? N/A
  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.) N/A
  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? N/A
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  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? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  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? 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? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  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? N/A
  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