Trial Review

Registering a new trial?

To achieve prospective registration, we recommend submitting your trial for registration at the same time as ethics submission.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR


Registration number
ACTRN12616000018415
Ethics application status
Approved
Date submitted
7/07/2015
Date registered
14/01/2016
Date last updated
15/05/2019
Date data sharing statement initially provided
15/05/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Study examining the effects of altering a diet's macronutrient composition on plasma ketone levels in women with gestational diabetes mellitus
Scientific title
A Randomised controlled trial (RCT) examining the effects of a modestly lower carbohydrate diet on plasma ketone levels in women with gestational diabetes mellitus (GDM)
Secondary ID [1] 287050 0
Nil
Universal Trial Number (UTN)
Nil
Trial acronym
MAMI GDM
(Macronutrient Adjustments in Mothers to Improve Gestational Diabetes Mellitus)
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gestational Diabetes Mellitus 295527 0
Condition category
Condition code
Reproductive Health and Childbirth 295802 295802 0 0
Antenatal care
Reproductive Health and Childbirth 295849 295849 0 0
Fetal medicine and complications of pregnancy
Metabolic and Endocrine 297334 297334 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Arm 1 Intervention - Main focus will be limiting daily carbohydrate intake to 135 g. Carbohydrates should be spread evenly through out the day, with 2 carbohydrate exchanges per main meal (3 times a day) and 1 exchange per mid meal (also 3 times a day). One exchange equals to consuming 15 g of carbohydrate and this proves to be a useful method of monitoring carbohydrate intake, particularly in individuals diagnosed with diabetes. A research dietitian will have ongoing contact with participants via phone (to arrange meetings) and during 4 face-to-face sessions (including a baseline and 3 other follow up visits in Week 2, Week 4 and Week 6, all lasting no more than an hour).

To prevent study bias, participants will be unaware of their group allocation. They will, however, receive a pictorial booklet containing acceptable carbohydrate portions of various foods. The study dietitian will also verbally guide participants on the acceptable amount and distribution of carbohydrates . A 3-day food record will be collected at baseline and in the last (6th or 7th) week of the study, where as a 24 hour recall will be conducted at 2 follow up visits to confirm diet compliance. Non-compliant participants will be re-educated. Food packages including breads, cereals, pasta and rice will be handed to women to help model portion size (i.e. what represents 1 exchange) and enhance participation rate.

The study is designed to last 6-7weeks (though 6 ideally), but this will depend on participant's availability and ability to attend all the face-to-face sessions.
Intervention code [1] 292271 0
Lifestyle
Intervention code [2] 292309 0
Treatment: Other
Comparator / control treatment
Arm 2 Control - People in the control group will have standard GDM care including a standard diet containing ~180-200g of carbohydrates/day, with a distribution pattern of 2-3 exchanges per main meal (3 times a day) and 1 exchange per mid meal (roughly 3 times a day). Similarly to the intervention group, control will not be informed of their group's allocation. They will have the same number of visits with the research dietitian, who will promote general healthy eating messages. Food packages will also be distributed (but to a lesser degree) to the control in order to 'mask' that they are in the control group.
Control group
Active

Outcomes
Primary outcome [1] 295501 0
Safety - which will be assessed by blood ketone measurements and medical symptom flags.

Timepoint [1] 295501 0
- 3 finger pricks/day on selected days (4th and 7th day of week 1 and week 6) prior to breakfast, lunch and dinner.
- Random ketone measurements at follow up visits 1 and 2.
Secondary outcome [1] 315713 0
Dietary compliance - which will be assess by 24 Hour Recalls and 3-day food record.
Timepoint [1] 315713 0
3-day food record (baseline and week 6), 24 hour recall (follow up visit 2 and 3).
Secondary outcome [2] 319617 0
Large/Small gestational age babies
Timepoint [2] 319617 0
After birth, to be assessed using medical records
Secondary outcome [3] 319642 0
Caesarian delivery
Timepoint [3] 319642 0
After birth, to be obtained from medical records
Secondary outcome [4] 319643 0
Baby's body composition
Timepoint [4] 319643 0
After birth, to be obtained from PEAPOD measurements

Eligibility
Key inclusion criteria
1. Women diagnosed with gestational diabetes mellitus (GDM) at 24-30 weeks gestation
2. Singleton pregnancy
3. Age between 18-45 years
Minimum age
18 Years
Maximum age
45 Years
Sex
Females
Can healthy volunteers participate?
No
Key exclusion criteria
1. Women with special dietary requirements (e.g. vegan/vegetarian, gluten free)
2. Existence of co-morbidities other than obesity, hypertension or dyslipidemia
3. Pre-existing diabetes
4. Undesirable lifestyle habits such as smoking and alcohol consumption
5. Pregnancy achieved by assisted reproduction (IVF)

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)
SCREENING: Women will be screened for eligibility at the end of Diabetes Sessions at the Antenatal Clinic. Eligible subjects handed information and consent papers to sign, and asked to provide contact details so that a letter of their next appointment with a 3-day food record could be mailed out. The food record will aim to capture intake of (non-consecutive) 2 weekdays and 1 day of the weekend.
ENROLLMENT: Women return for their first official visit for the study, bringing completed 3-day food records. Dietitian is to assist women in completing their Enrollment form which aims to capture demographic data ranging from age to past and present medical conditions.
RANDOMISATION: Women will be randomised with an envelope block randomization technique. This ensures that study groups will be equal in size and uniformly distributed by key characteristics – age (> 30 and <30 years old) and weeks gestation (>28 and <28 weeks). With the exception of the research dietitian, all other research members and participants will be blinded to group allocations
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Block randomisation
We will sort experimental units into 4 groups of similar characteristics. They include:
1. Age > 30 yeas
2. Age < 30 (30 inclusive) years
3. >28 Weeks gestation
4. <28 (28 inclusive) Weeks gestation
Treatment will then be assigned at random within the blocks using sealed envelopes
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


The people analysing the results/data
Intervention assignment
Parallel
Other design features
NA
Phase
Not Applicable
Type of endpoint/s
Safety
Statistical methods / analysis
The study is designed to provide 80% statistical power to detect approximately 0.04 mmol difference in blood ketone levels with 25 subjects in each of the two groups. We will aim to recruit 65 subjects, with allowance of 25% (15 subjects) to dropout. Calculations were based on a study by Gin and colleagues, published in 2006. A paired 2 sample t-test will be used to assess between group changes from baseline to final outcomes.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
1/02/2016
Actual
7/04/2016
Date of last participant enrolment
Anticipated
Actual
15/03/2018
Date of last data collection
Anticipated
Actual
31/05/2018
Sample size
Target
65
Accrual to date
Final
45
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 4014 0
Royal Prince Alfred Hospital - Camperdown
Recruitment hospital [2] 7258 0
Campbelltown Hospital - Campbelltown
Recruitment postcode(s) [1] 15025 0
2560 - Campbelltown

Funding & Sponsors
Funding source category [1] 291606 0
University
Name [1] 291606 0
The University of Sydney
Country [1] 291606 0
Australia
Primary sponsor type
University
Name
The University of Sydney
Address
Charles Perkins Centre, John Hopkins Drive (off Missenden Road), Camperdown NSW 2006
Country
Australia
Secondary sponsor category [1] 290278 0
None
Name [1] 290278 0
Address [1] 290278 0
Country [1] 290278 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 293141 0
Royal Prince Alfred Hospital Ethics Committe
Ethics committee address [1] 293141 0
Missenden Road, Camperdown NSW 2006, Australia
Ethics committee country [1] 293141 0
Australia
Date submitted for ethics approval [1] 293141 0
11/08/2015
Approval date [1] 293141 0
15/12/2015
Ethics approval number [1] 293141 0
X15-0298

Summary
Brief summary
To our knowledge no study investigated serum ketone levels in Gestational Diabetes Mellitus (GDM) pregnancy with a modestly lower carbohydrate diet. Our primary aim is to document a range of blood ketone in women on a routine GDM diet (180-200 g carbohydrates/day) and a modestly lower carbohydrate diet (135g carbohydrates/day). The 135 g of carbohydrate/day is an absolute amount of carbohydrate which is in line with Institute of Medicine (IOM) recommendation for carbohydrate intake during pregnancy. We also aim to examine the effect of modestly lower carbohydrate diet on the risk of ketonemia in GDM pregnancy. We hypothesise that when compared to a routine GDM diet, a modestly lower carbohydrate diet will not increase ketone levels in GDM pregnancy, nor will it increase the risk of adverse pregnancy outcomes including risk of large/small gestational age babies and caesarean delivery. If our hypotheses are proven to be correct, perhaps prescribing a modestly lower carbohydrate diet to no less than 135g/day will be the new standard for treatment of GDM.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 58638 0
Prof Jennie Brand-Miller
Address 58638 0
Level 6 West, The Hub
D17 Charles Perkins Centre
John Hopkins Drive (off Missenden Road),
The University of Sydney
Camperdown, NSW 2006
Country 58638 0
Australia
Phone 58638 0
+61 2 93513759
Fax 58638 0
Email 58638 0
[email protected]
Contact person for public queries
Name 58639 0
Jovana Mijatovic
Address 58639 0
Level 2 North, The Hub D17 Charles Perkins Centre John Hopkins Drive (off Missenden Road), The University of Sydney Camperdown, NSW 2006
Country 58639 0
Australia
Phone 58639 0
+61 2 86271341
Fax 58639 0
Email 58639 0
[email protected]
Contact person for scientific queries
Name 58640 0
Jennie Brand-Miller
Address 58640 0
Level 6 West, The Hub
D17 Charles Perkins Centre
John Hopkins Drive (off Missenden Road),
The University of Sydney
Camperdown, NSW 2006
Country 58640 0
Australia
Phone 58640 0
+61 2 93513759
Fax 58640 0
Email 58640 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
This was not part of our agreement with Ethics.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

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

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseEffects of a modestly lower carbohydrate diet in gestational diabetes: A randomized controlled trial.2020https://dx.doi.org/10.1093/ajcn/nqaa137
N.B. These documents automatically identified may not have been verified by the study sponsor.