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Trial registered on ANZCTR


Registration number
ACTRN12620000968976
Ethics application status
Approved
Date submitted
7/07/2020
Date registered
28/09/2020
Date last updated
7/06/2021
Date data sharing statement initially provided
28/09/2020
Type of registration
Prospectively registered

Titles & IDs
Public title
The Effect of a High Dietary Intake of Resistant Starch on Blood Glucose Levels in Women with Gestational Diabetes.
Scientific title
The Effect of a High Dietary Intake of Resistant Starch on Blood Glucose Levels and the Gut Microbiota in Women with Gestational Diabetes.
Secondary ID [1] 301699 0
Nil known
Universal Trial Number (UTN)
U1111-1254-8361
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gestational Diabetes 318151 0
Condition category
Condition code
Metabolic and Endocrine 316169 316169 0 0
Diabetes
Reproductive Health and Childbirth 316477 316477 0 0
Fetal medicine and complications of pregnancy

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Resistant Starch (RS) Dietary Intervention
Women who are randomised to either of the two dietary intervention groups (RS Diet or RS Supp). Both groups will receive dietary education on consuming a high RS diet from whole foods. All RS dietary education will be conducted face-to-face at Fiona Stanley Hospital by the Principal Investigator, who is a Dietitian with over 30 years experience. The education will be conducted during a single 30 minute individual session. A standardised teaching plan will be used and participants will be provided with written nutrition education material and sample menus specifically developed for this study. They will also receive a "Gut Feeling" cookbook which was written by researchers at Edith Cowan University and is available for purchase from www.ecu.edu.au/schools/medical-and-health-sciences/our-research/systems-and-intervention-research-centre-for-health/news-and-events/sirch/2017/07/gut-feeling-mindful-menus-for-the-microbiome The RS education tools and strategies have been piloted by this group in a non-pregnant population and achieved a median increase in dietary RS intake of greater than 6.6 g RS per day. The high RS diet will commence on Day 3 of the trial and continue until delivery of the baby.

RS Supplement (RS Supp)
In addition to a high RS diet, the RS Supp group will be instructed to begin to consume a powdered RS supplement of high-amylose maize type 2 resistant starch (HAMS-RS2). The supplement will be stirred into cold foods such as yoghurt, smoothies, mashed banana and hummus. Participants will introduce HAMS over a two-day adjustment period by consuming 20 g per day, half a sachet morning and night for two days. Then, increasing to a split dose of 2 x 20 g per day for the remainder of their pregnancy. The RS supplement contains 60 percent RS type 2. The final amount of RS in the 40 g of HAMS per day will be 24 g.

Participants will have face-to-face or telephone contact with the Chief Investigator approximately every 2 weeks to assess adherence to the diet and supplement (if applicable), to remind them of the next steps in the study protocol and to answer questions. The last contact with the participants will be at 1-week post-partum. Adherence to the dietary and supplement interventions will be monitored via 3-day food diaries (Baseline to Day 3, Days 7-9 and three consecutive days in the 35th week of gestation), RS supplement consumption records, measurement of change in gut microbiota and increase in stool short chain fatty acid content.

Intervention code [1] 318003 0
Lifestyle
Intervention code [2] 318004 0
Treatment: Other
Comparator / control treatment
The control group will receive standard dietary advice for women with Gestational Diabetes as per usual care at Fiona Stanley Hospital. This will include written information and sample menus that do not specifically target high RS foods. The education resource used in standard treatment is produced by the Dietetic Department at King Edward Memorial Hospital (KEMH) and is called KEMH: Healthy Eating for Gestational Diabetes. It is available to download from their website https://kemh.libguides.com/library/subject_guides/nutrition_womens_health
Control group
Active

Outcomes
Primary outcome [1] 324351 0
Any change in Fasting Blood Glucose (FBG) will be assessed using a serum glucose assay or finger-prick glucose monitor.
Timepoint [1] 324351 0
Baseline, Day 7 of intervention and 36-weeks' gestation
Secondary outcome [1] 384414 0
Any change in postprandial glucose levels will be assessed using downloaded data from a finger-prick blood glucose monitor or glucose sensor data.
Timepoint [1] 384414 0
Baseline, Day 7 of intervention and at 36 weeks' gestation
Secondary outcome [2] 384415 0
Any change in the number of episodes of 2-hour post-prandial glucose levels greater than or equal to 6.7 mmol/L, assessed by review of downloaded data from a finger-prick blood glucose monitor or glucose sensor data.
Timepoint [2] 384415 0
Baseline, Day 7 of intervention and at 36 weeks' gestation
Secondary outcome [3] 384416 0
Any change in the time spent in range (TIR) for glucose (3.5-7.8 mmol/L) will be assessed using TIR calculated by software associated with a glucose sensor.
Timepoint [3] 384416 0
Baseline, Day 7 of intervention and at 36 weeks' gestation
Secondary outcome [4] 384417 0
Any change in the percentage of women requiring insulin to control blood glucose levels will be assessed using a participant glucose monitoring diary.
Timepoint [4] 384417 0
Day 7 of intervention and 36-weeks' gestation
Secondary outcome [5] 384419 0
An alteration in stool microbial composition will be assessed using 16S rDNA sequencing.
Timepoint [5] 384419 0
Baseline, day 7 of intervention, 36-weeks' gestation and 1 week postpartum
Secondary outcome [6] 384420 0
Any change in gut microbial fermentation will be assessed by examining the short chain fatty acid composition (acetic acid, propionic acid, butyric acid) of stool samples via high-performance liquid chromatography.
Timepoint [6] 384420 0
Baseline, Day 7 of intervention, 36-weeks' gestation and 1 week postpartum
Secondary outcome [7] 385258 0
Any change in rate of preeclampsia will be assessed using hospital medical records.
Timepoint [7] 385258 0
1 week post-partum
Secondary outcome [8] 385259 0
Any change to health care costs will be calculated using hospital records of outpatient clinic appointments and Diagnostic Related Groups (DRG)
Timepoint [8] 385259 0
1 week post-partum
Secondary outcome [9] 386447 0
Any change in rate of Caesarean section delivery will be assessed using hospital medical records.
Timepoint [9] 386447 0
1 week post-partum
Secondary outcome [10] 386448 0
Any change in rate of macrosomia will be assessed using hospital medical records.
Timepoint [10] 386448 0
1 week post-partum
Secondary outcome [11] 386449 0
Any change in rate of neonatal hypoglycaemia will be assessed using hospital medical records.
Timepoint [11] 386449 0
1 week post-partum
Secondary outcome [12] 386450 0
Any change in rate of Neonatal Intensive Care Unit admission will be assessed using hospital medical records.
Timepoint [12] 386450 0
1 week post-partum

Eligibility
Key inclusion criteria
Diagnosed with GDM by a 75 g Oral Glucose Tolerance Test (OGTT) between 24-30 weeks of pregnancy and greater than or equal to 18 years of age. A diagnosis of GDM is made using the International Association of Diabetes in Pregnancy Study Groups (IADPSG) diagnostic criteria of one or more values reaching the following levels – Fasting glucose of greater than or equal to 5.1 mmol/L, 1-hour of greater than or equal to 10.0 mmol/L, 2-hours of greater than or equal to 8.5 mmol/L.
Minimum age
18 Years
Maximum age
No limit
Gender
Females
Can healthy volunteers participate?
No
Key exclusion criteria
Early diagnosis of GDM before 24 weeks; Overt Diabetes in Pregnancy; Type 1 Diabetes; T2DM; poorly controlled hypothyroidism; Graves’ Disease; twin pregnancy; breastfeeding; vegetarian; vegan; irritable bowel syndrome; inflammatory bowel disease; previous bariatric surgery; history of an eating disorder; antibiotic use in the past 3 months; use of steroids, antipsychotics, metformin, laxatives, fibre supplements or probiotic supplement; allergy to adhesives; any major medical disorder; any psychosocial issues likely to impact on ability to adhere to study protocol.

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)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
In a study by Asemi et al (2013), the average GDM patient has a mean FBG of 5.175 +/- 0.86 mmol/L. Our study aims to demonstrate a reduction in FBG of 0.5 mmol/L, which corresponds to a medium Cohen’s effect size (d = 0.581). Based on a repeated-measures design with three groups (Control, RS Diet, RS Supp) and three time points (Baseline, Day 7 of intervention and 36-week gestation [approximately Day 56]), a minimum sample size of 36 (i.e. 12 per group) is required to detect a medium within-between interaction effect (Cohen’s f = 0.25) at 80 percent power and 5 percent level of significance. Assuming that (i) 50 percent of women will require insulin within the first two weeks and not continue the study protocol, and (ii) an attrition rate of around 20 percent, the final total sample size required is 90 (i.e. 30 per group).

SPSS will be used to perform mixed model ANOVA to look at change within and between groups for short chain fatty acids (SCFA) and measures of glycaemic control.
PRIMER non-parametric statistical software package will be used for PERMANOVA to assess change within and between groups for stool microbial composition. Distance based linear modelling (DistLM) will look at the correlation between change in microbiota or SCFA and measures of glycaemia.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
WA
Recruitment hospital [1] 17029 0
Fiona Stanley Hospital - Murdoch
Recruitment postcode(s) [1] 30698 0
6150 - Murdoch

Funding & Sponsors
Funding source category [1] 306136 0
Government body
Name [1] 306136 0
Western Australian Department of Health
Address [1] 306136 0
189 Royal St, East Perth, Western Australia, 6004
Country [1] 306136 0
Australia
Funding source category [2] 306147 0
University
Name [2] 306147 0
Edith Cowan University
Address [2] 306147 0
270 Joondalup Drive, Joondalup, Western Australia, 6027
Country [2] 306147 0
Australia
Primary sponsor type
University
Name
Edith Cowan University
Address
Edith Cowan University
270 Joondalup Drive
Joondalup WA 6027
Country
Australia
Secondary sponsor category [1] 306858 0
None
Name [1] 306858 0
Address [1] 306858 0
Country [1] 306858 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 306353 0
South Metropolitan Health Service Human Research Ethics Committee
Ethics committee address [1] 306353 0
Fiona Stanley Hospital
11 Robin Warren Drive
Murdoch 6150
Western Australia
Ethics committee country [1] 306353 0
Australia
Date submitted for ethics approval [1] 306353 0
27/07/2020
Approval date [1] 306353 0
29/09/2020
Ethics approval number [1] 306353 0
RGS0000004140
Ethics committee name [2] 308694 0
Edith Cowan University Human Reserach Ethics Committee
Ethics committee address [2] 308694 0
270 Joondalup Drive
JOONDALUP
Western Australia 6027
Ethics committee country [2] 308694 0
Australia
Date submitted for ethics approval [2] 308694 0
06/10/2020
Approval date [2] 308694 0
08/10/2020
Ethics approval number [2] 308694 0
2020-01960-LATINO

Summary
Brief summary
The study will investigate whether a diet high in foods rich in Resistant Starch (RS), with or without the addition of a RS supplement, changes the gut microbial composition and blood glucose control compared with usual dietary advice (control) in women with newly diagnosed Gestational Diabetes (GDM).
Data will be collected at Baseline, Day 7 of intervention, and 36-weeks of gestation and include dietary RS consumption, stool microbial analysis and short chain fatty acid content, fasting and post-meal blood glucose levels, time in optimal glycaemic range, the requirement for glucose-lowering medication, maternal and neonatal health outcomes, and health care costs.
We hypothesise that, compared with standard GDM dietary advice, women with a high dietary intake of RS beginning at the diagnosis of GDM will show a reduction in fasting blood glucose levels and other measures of blood glucose control.

Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 103586 0
Mrs Cathy Latino
Address 103586 0
Fiona Stanley Hospital
11 Robin Warren Drive
Murdoch 6150
Western Australia
Country 103586 0
Australia
Phone 103586 0
+61 8 61672962
Fax 103586 0
Email 103586 0
cathy.latino@health.wa.gov.au
Contact person for public queries
Name 103587 0
Mrs Cathy Latino
Address 103587 0
Fiona Stanley Hospital
11 Robin Warren Drive
Murdoch 6150
Western Australia
Country 103587 0
Australia
Phone 103587 0
+61 8 61672962
Fax 103587 0
Email 103587 0
cathy.latino@health.wa.gov.au
Contact person for scientific queries
Name 103588 0
Mrs Cathy Latino
Address 103588 0
Fiona Stanley Hospital
11 Robin Warren Drive
Murdoch 6150
Western Australia
Country 103588 0
Australia
Phone 103588 0
+61 8 61672962
Fax 103588 0
Email 103588 0
cathy.latino@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?
All participant data collected during the trial after de-identification
When will data be available (start and end dates)?
Beginning 3 months after and ending 5 years after main results publication
Available to whom?
Only researchers who provide a methodologically sound proposal
Available for what types of analyses?
Any purpose
How or where can data be obtained?
Access subject to approval by Principal Investigator
cathy.latino@health.wa.gov.au
What supporting documents are/will be available?
No other documents available
Summary results
No Results