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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] 291817 0
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 303058 0
Condition category
Condition code
Metabolic and Endocrine 302518 302518 0 0
Diabetes
Reproductive Health and Childbirth 302551 302551 0 0
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] 297930 0
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] 301932 0
Fasting capillary glucose level as measured with a home glucometer
Timepoint [1] 301932 0
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] 334292 0
Requirement for insulin as assessed by the physician based on fasting glucose levels, gestation, fetal growth and maternal weight
Timepoint [1] 334292 0
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?
No
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
66
Accrual to date
Final
69
Recruitment in Australia
Recruitment state(s)
WA
Recruitment hospital [1] 7900 0
King Edward Memorial Hospital - Subiaco
Recruitment postcode(s) [1] 15858 0
6008 - Subiaco

Funding & Sponsors
Funding source category [1] 296319 0
Hospital
Name [1] 296319 0
King Edward Memorial Hospital
Country [1] 296319 0
Australia
Funding source category [2] 296345 0
Self funded/Unfunded
Name [2] 296345 0
Dr Dorothy Graham
Country [2] 296345 0
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] 295277 0
None
Name [1] 295277 0
Address [1] 295277 0
Country [1] 295277 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 297550 0
WNHS Human Research Ethics Committee
Ethics committee address [1] 297550 0
King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008
Ethics committee country [1] 297550 0
Australia
Date submitted for ethics approval [1] 297550 0
01/05/2017
Approval date [1] 297550 0
14/06/2017
Ethics approval number [1] 297550 0

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 74406 0
Dr Meg Henze
Address 74406 0
King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008
Country 74406 0
Australia
Phone 74406 0
+61 8 6458 2222
Fax 74406 0
Email 74406 0
[email protected]
Contact person for public queries
Name 74407 0
Meg Henze
Address 74407 0
King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008
Country 74407 0
Australia
Phone 74407 0
+61 8 6458 2222
Fax 74407 0
Email 74407 0
[email protected]
Contact person for scientific queries
Name 74408 0
Meg Henze
Address 74408 0
King Edward Memorial Hospital
Bagot Road
Subiaco WA 6008
Country 74408 0
Australia
Phone 74408 0
+61 8 6458 2222
Fax 74408 0
Email 74408 0
[email protected]

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.TypeCitationLinkEmailOther DetailsAttachment
12566Study protocol  [email protected]
12567Informed consent form  [email protected]
12568Statistical analysis plan  [email protected]
12569Clinical study report  [email protected]
12570Ethical approval  [email protected]



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseThe effect of bedtime snacks on fasting blood glucose levels in gestational diabetes mellitus.2022https://dx.doi.org/10.1111/dme.14718
N.B. These documents automatically identified may not have been verified by the study sponsor.