ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12617000659303

Ethics application status

Approved

Date submitted

1/05/2017

Date registered

8/05/2017

Date last updated

16/07/2021

Date data sharing statement initially provided

2/04/2019

Type of registration

Prospectively registered

Titles & IDs

Public title

The effect of high carbohydrate and low carbohydrate suppers on fasting blood glucose levels (BGLs) in gestational diabetes mellitus (GDM): GDM Supper Study

Scientific title

The effect of high carbohydrate and low carbohydrate suppers on fasting blood glucose levels (BGLs) in gestational diabetes mellitus (GDM)

Secondary ID [1]

None

Universal Trial Number (UTN)

None

Trial acronym

Linked study record

No linked study

Health condition

Health condition(s) or problem(s) studied:

gestational diabetes

Condition category

Condition code

Metabolic and Endocrine

Diabetes

Reproductive Health and Childbirth

Fetal medicine and complications of pregnancy

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Women will be informed of the study at their first education class. Women will be enrolled into the study following their initial Dietitian review if they have greater than or equal to two fasting BGLs in the preceding week between 4.7-5.4 mmol/L and post-prandial levels not requiring insulin treatment, following informed consent being obtained. The dietitians delivering the intervention all have extensive clinical experience of a minimum of 5 years. There is not expected to be any carry-over effect of the treatments so the "wash out" period between treatments is the intervening daytime only.

Participants will be asked to:
a take a standardised, healthy carbohydrate based snack for five days
b take a standardised, higher protein, lower carbohydrate snack for five days
c have five days without any supper snack
d The snack will be consumed at least 2 hours after dinner (between 7pm and 12am depending on the timing of their dinner between 5pm and 8pm)
e record fasting and post-prandial BGLs daily for the fifteen day period
f record activity levels (low/moderate/high) intensity and record sleep quality (poor/moderate/good) each day

If they consent to participating in the study, they will be randomly allocated to an order in which to take their snacks:
1 Higher carbohydrate snack: Yoghurt tub (175g) and an apple (medium ~150g)
Yoghurt = 88cal, 12.3g CHO, 8.8g protein, 0.2g fat
Apple = 68cal, 14.6g CHO, 0.4g protein, 0g fat
TOTAL = 156cal; 26.9g carbohydrate; 9.2g protein, 0.2g fat

2 Lower carbohydrate snack: Almonds (10 nuts) and 2 squares (20g) of dark chocolate
Almonds = 72cal, 0.6g CHO, 2.3g protein, 6.6g fat
Dark chocolate = 112cal, 6.8g CHO, 1.9g protein, 8.2g fat
TOTAL = 184cal; 7.4g CHO, 4.2g protein, 14.8g fat

3 No snack

Food will be provided to the study participants in esky containers for transport home. It will be prepared by kitchen staff at the hospital. Women will record their BGLs, quality of sleep and activity levels each day on a record sheet provided to them (attached). They will also record with a tick whether they complied with the prescribed snack.

As the patients are not on insulin there are no safety concerns regarding missing an evening snack. If a participant requires insulin while the study is ongoing (as decided by the physician) then their participation in the study is ceased.

Intervention code [1]

Treatment: Other

Comparator / control treatment

Crossover design, ie participants are their own controls. The control treatment is that currently recommended by the hospital which is the high carbohydrate snack (apple and yoghurt) This is currently the standard recommendation for women with gestational diabetes and elevated fasting glucose levels by dietitians in clinical practice

Control group

Active

Outcomes

Primary outcome [1]

Fasting capillary glucose level as measured with a home glucometer

Timepoint [1]

The outcome is assessed by the participant checking their fasting capillary glucose every day during the 15 day period (each day of the 3 different 5 day intervention periods) of the trial.

Secondary outcome [1]

Requirement for insulin as assessed by the physician based on fasting glucose levels, gestation, fetal growth and maternal weight

Timepoint [1]

At the completion of the 15 day intervention or at any timepoint if concern is raised by the participant or treating dietitian regarding the level of their fasting or postprandial glucose levels

Eligibility

Key inclusion criteria

a Have gestational diabetes diagnosed on routine oral glucose tolerance test. OGTT will diagnose gestational diabetes if fasting BSL is greater than or equal to 5.1, 1 hour reading is greater than or equal to 10, 2 hours greater than or equal to 8.5.
b Be on diet control (no oral hypoglycaemic agents or insulin)
c Have two or more fasting BGLs of 4.7-5.4mmol/L in the week prior to recruitment
d Have a singleton pregnancy
e Are between 24 and 34 weeks gestation
f Have not had hospital admissions or Celestone therapy for the 2 weeks of the study
g Have no food allergies or intolerances that preclude them taking the snack
h Are compliant with BGL monitoring
i Fasting BGL recorded between 6am to 8am with a minimum time of 8 hours since their evening snack
j Are capable of giving informed consent
k Are women aged greater than or equal to 18 years of age
l Have dinner between the hours of 5pm and 8 pm, with a 2 hour minimum time between evening meal and evening snack

Minimum age

18 Years

Maximum age

50 Years

Sex

Females

Can healthy volunteers participate?

Key exclusion criteria

a Requiring NovoRapid (fast acting insulin) with meals or requiring Protaphane (long acting insulin) during the two week period (as per treating physician’s decision)
b Patients on metformin or other medications which may affect glucose metabolism (as per treating physician’s decision) during the study
c Shift workers, or irregular meal times for any other reason
d greater than or equal to 3 fasting BGLs greater or equal to 5.2mmol/L in the week prior to recruitment
e Macrosomic foetus, defined as AC greater than 90 percentile or polyhydramnios
f Women who require an interpreting service
g Women who have had bariatric surgery

Study design

Purpose of the study

Treatment

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Allocation concealment is being used using sealed envelopes

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Concealed envelope randomisation with permuted block randomisation

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Crossover

Other design features

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

A sample size of 66 has been calculated to be enough to show a 0.2mmol drop in fasting blood glucose levels (with a standard deviation of 0.5mmol/l) using an alpha value of 0.05 and a beta of 0.9. Student’s t test will be used to compare the average fasting blood glucose levels. If underlying assumptions for the t-test are not met, non-parametric tests will be used. Bonferonni corrections will be used when multiple tests are performed.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

1/06/2017

Actual

25/08/2017

Date of last participant enrolment

Anticipated

1/09/2019

Actual

3/11/2020

Date of last data collection

Anticipated

16/09/2020

Actual

24/11/2020

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

Recruitment hospital [1]

King Edward Memorial Hospital - Subiaco

Recruitment postcode(s) [1]

6008 - Subiaco

Funding & Sponsors

Funding source category [1]

Hospital

Name [1]

King Edward Memorial Hospital

Address [1]

King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008

Country [1]

Australia

Funding source category [2]

Self funded/Unfunded

Name [2]

Dr Dorothy Graham

Address [2]

King Edward Memorial Hospital
Bagot Rd Subiaco, 6008, WA

Country [2]

Australia

Primary sponsor type

Individual

Name

Dr Dorothy Graham

Address

King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

WNHS Human Research Ethics Committee

Ethics committee address [1]

King Edward Memorial Hospital 
Bagot Road
Subiaco WA 6008

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

01/05/2017

Approval date [1]

14/06/2017

Ethics approval number [1]

Summary

Brief summary

Diabetes in pregnancy is the most common metabolic dysfunction in pregnancy.  Many women are managed with diet control alone.  It is therefore essential that women are receiving accurate nutritional advice.

Current practice at our hospital is to advise women to have a bedtime snack to help meet the caloric requirements of pregnancy, and with the expectation that it may suppress hepatic gluconeogenesis thus achieving lower fasting blood glucose levels (BGLs).  Recommending supper in GDM is widely practiced across Australia and is contained in the Dietitians Association of Australia resources, and supported by the Canadian and American Diabetes Associations’ Guidelines; however, there is no strong or recent evidence to support this.

This study aims to recruit 66 women and measure the effect of two different snacks: a higher carbohydrate snack (apple and yoghurt) and a lower carbohydrate snack (nuts and dark chocolate) as compared to no snack, to see what influence each of these has on fasting BGLs.  Each snack will be consumed for five consecutive days.  Women will be randomly allocated an order in which to consume each snack.  Women will also be required to record their activity levels each day, in order to monitor the effect that this has on fasting BGLs

It is expected that women will have lower fasting BGLs when consuming either snack than when they are not having a snack.  It is also expected that those women with higher physical activity levels will have lower fasting BGLs.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Meg Henze

Address

King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008

Country

Australia

Phone

+61 8 6458 2222

Fax

meg.henze@health.wa.gov.au

Contact person for public queries

Name

Meg Henze

Address

King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008

Country

Australia

Phone

+61 8 6458 2222

Fax

meg.henze@health.wa.gov.au

Contact person for scientific queries

Name

Meg Henze

Address

King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008

Country

Australia

Phone

+61 8 6458 2222

Fax

meg.henze@health.wa.gov.au

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

Yes

What data in particular will be shared?

Blood glucose levels- deidentified

When will data be available (start and end dates)?

On completion of the trial. The start date will depend on when the trial recruitment finishes but anticipated to be 2021. Data will be available immediately following publication for 3 years

Available to whom?

Journal reviewers

Available for what types of analyses?

Statistical analyses

How or where can data be obtained?

Electronic database

What supporting documents are/will be available?

Doc. No.	Type	Email
12566	Study protocol	dorothy.graham@health.wa.gov.au
12567	Informed consent form	dorothy.graham@health.wa.gov.au
12568	Statistical analysis plan	dorothy.graham@health.wa.gov.au
12569	Clinical study report	dorothy.graham@health.wa.gov.au
12570	Ethical approval	dorothy.graham@health.wa.gov.au

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	The effect of bedtime snacks on fasting blood glucose levels in gestational diabetes mellitus.	2022	https://dx.doi.org/10.1111/dme.14718

N.B. These documents automatically identified may not have been verified by the study sponsor.

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Documents added automatically