EAL

ORP: Structured Programs and Interventions (2014)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To evaluate whether a four-step multi-disciplinary protocol of antenatal care for overweight and obese women would reduce the incidence of gestational diabetes.

Inclusion Criteria:

Female
Pregnant
English speaking
Did not intend to relinquish their infant
Did not have multiple gestation
Were able to attend hospital for antenatal care
Overweight (BMI 25 to 29.9) or obese (BMI more than 29.9) on standard body mass index determination (height/m²).

Exclusion Criteria:

Any individual not meeting the inclusion criteria.

Description of Study Protocol:

Recruitment

Participants were recruited through the maternity service of a public general hospital serving a socioeconomically disadvantaged area, if inclusion criteria was met. 490 women were approached to participate in the trial, 198 were considered overweight or obese, 13 did not satisfy the inclusion criteria. Consent was obtained from 134 women who were subsequently enrolled in the trial. Two women withdrew consent before randomization took place resulting in 132 being randomized. This represented 71.4% of the total eligible group.

Design

Randomized, controlled trial.

Blinding Used

Outcome data for mother and infant were audited by a nurse independent of clinical care pathways and blinded to randomization status.

Intervention

Randomization to the intervention or the control group occurred using a computer-generated, numbered, sealed, opaque envelope, stratified by category (overweight or obese), which were only opened by the midwife after each woman's enrollment was complete
Women in the control group were allocated to routine public antenatal care (consisting of midwifery, obstetrician and general practitioner ante-natal clinics and access to high-risk antenatal clinics if indicated on medical grounds). Women in the control group who were subsequently diagnoses with gestational diabetes were referred to a public obstetric diabetes clinic for ongoing care.
Participants randomized to the intervention (treatment) arm underwent a four-step, multi-disciplinary approach to the management of obese pregnant women. The four steps were:
- Continuity of care by a single maternity care provider
- Assessing weight gain at each antenatal visit
- A brief (five-minute) intervention by a food technologist before each visit
- An assessment by a clinical psychologist with individualized, solution-focused treatment plan implemented for and needs identified.
If women in the intervention (treatment) arm were diagnosed with gestational diabetes, they remained in the obesity clinic for care but were treated utilizing identical clinical care guidelines as women in the general obstetric diabetes clinic.

Statistical Analysis

A sample size of 126 women could detect a difference in gestational diabetes of 33% compared to 11% with a power of 80% and a error of 5%. 63 women were required in both the control and treatment groups.
Data were analyzed using the Stata V10.0 statistical software program
Baseline variables (characteristics and assessments) that were categorical in nature were compared using chi-square tests or Fisher exact tests for small expected cell size. Age was compared using student's T-test.
The categorical outcome variable (gestational diabetes) was compared looking at a proportion between groups carried out using unweighted logistic regression, adjusting for confounding factors. The outcome continuous variables (weight gain and birth weight) were compared using linear regression.
A significance level of 5% was used in the study.

Data Collection Summary:

Timing of Measurement

A baseline questionnaire was completed after enrollment in the study during the first ante-natal clinic visit to assess diet, lifestyle, demographic characteristics and ante-natal variables. Labor and delivery data and final incidence of gestational diabetes were audited from medical records.

Dependent Variables

Primary outcome: Prevalence of the combined diagnoses of decreased gestational glucose tolerance and gestational diabetes mellitus. Women underwent, on consecutive days, a 75g fasting two-hour glucose tolerance test and then a 100g fasting three-hour glucose tolerance test. The primary outcome depended upon the 75g glucose tolerance test meeting the WHO criteria of more than 6.6mmol per L (decreased gestational glucose tolerance) or more than 7.7mmol per L (gestational diabetes mellitus).
Secondary outcomes:
- Weight gain in pregnancy defined as the difference between the weight at study enrollment and the weight at the onset of labor
- Birth weight as measured by the attending midwife immediately following birth on calibrated neonatal scales.

Independent Variables

Assignment to standard ante-natal care (control) vs. assignment to the four-step multi-disciplinary treatment.

Description of Actual Data Sample:

Initial N: 132 women were randomized
Attrition (final N): Eight patients withdrew from the trial, resulting in a final N=124
Age: Mean age 28.3±0.63 years in the treatment group; 29.5±0.71 years in the control group. This did not differ significantly.

Ethnicity

Breakdown of race includes:

Asian: 13% (treatment group), 26% (control group)
Caucasian: 79% (treatment group), 67% (control group)
Other races: 8% (treatment group), 7% (control group).

Other Relevant Demographics

No significant differences were described in terms of antenatal, demographic or health behavior variables between the treatment and control groups. Household income was not reported; however, authors did dictate that the participants came from a socioeconomically disadvantaged area.

Anthropometrics

Percentage of patients in each BMI category (overweight or pre-obese, Obese I, Obese II and Obese III) did not differ between treatment and control groups.

Location

Melbourne, Australia.

Summary of Results:

Key Findings

Comparisons of primary and secondary outcome variables:

Outcomes	Treatment (N=63)	Control (N=61)	Test Statistics
Gestational diabetes
Yes	4 (6)	17 (29)	Z=-2.02; P=0.043
No	59 (94)	41 (71)
Weight gain during pregnancy (kg)	7.0 (0.65)	13.8 (0.67)	P<0.001; 95% CI: 4.3kg to 9.1kg
Birthweight of baby (kg)	3.5 (0.07)	3.4 (0.10)	P=0.162

*Gestational Diabetes reported as frequency (%); weight gain and birthweight reported as mean (SE).

Other Findings

The intervention was associated with changes in diet, as recorded by the food technologist at every visit where women were asked to itemize their food consumption of the previous day. The intervention resulted in:

Increased:
- Consumption of water (47 participants during the final visit compared to two participants during the first visit)
- Fresh fruit (42 participants during the final visit compared to five participants during the first visit)
- Fresh vegetables (42 participants during the final visit compared to 11 participants during the first visit).
Reductions in:
- Consumption of carbonated drinks (23 participants during the final visit compared to 61 participants during the first visit)
- Juices (47 participants during the final visit compared to two participants during the first visit)
- Fast food (10 participants during the final visit compared to 19 participants during the first visit).

Author Conclusion:

The results indicate that a four-step intervention can reduce the incidence of gestational diabetes and maternal weight gain in pregnancy, without an impact upon birth weight
The average cost for each participant for the dietary intervention with the food technologist was $78.75 and the cost per participant was $88.50 for screening and intervention, as needed, with a psychologist. The expense could be considered against the potential savings that may be achieved from women who no longer require attendance at diabetes ante-natal clinic where they see a physician ($80), dietitian ($25) and diabetes educator ($25) with a combined cost of $130 at each clinic visit.
More research is needed to determine whether components of this intervention would have similar impact in populations with lower prevalence of gestational diabetes.

Funding Source:

Not-for-profit

Telstra Community Development Trust (Australian not-for-profit organization with tax-exempt status)

Other non-profit:

Reviewer Comments:

Recruitment was done at one clinic in a socioeconomic challenged area with a higher incidence of obesity and diabetes than the general population. The sample was chosen for convenience.

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?		No
	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?	No
	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?	No
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.)	Yes
	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?	N/A
	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?	No
	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?	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?	Yes
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?	Yes
	6.6.	Were extra or unplanned treatments described?	No
	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)?	No
	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