Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT03547960 |
| Other study ID # |
IRAS ID: 230813 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
Early Phase 1
|
| First received |
|
| Last updated |
|
| Start date |
May 30, 2018 |
| Est. completion date |
March 17, 2021 |
Study information
| Verified date |
May 2022 |
| Source |
Imperial College London |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The primary aim of this study is to evaluate the effect of a soluble fibre supplement in the
development of gestational diabetes in women at high-risk. The secondary aim will be to
evaluate the effect of the soluble fibre supplement on glycaemic control in high-risk women
who develop gestational diabetes in early pregnancy.
DESIGN The study plans to conduct a randomised open label controlled study to evaluate the
effect of the consumption of soluble fibre, from early to mid-pregnancy, on the incidence of
gestational diabetes, insulin sensitivity, insulin secretion and metabolic control in GDM
diagnosed participants.
POPULATION The study team will be studying women with diagnosis of gestational diabetes in
previous pregnancies, (considered as high-risk) aged >18 years.
TREATMENT Participants in the treatment arms will be 5 gr of Guar gum fibre supplement with
meals three times a day (total daily 15 g). Participants in the placebo arms will be taking 5
gr of Cellulose three times a day (total daily dose 15 g).
DURATION Participants will be involved for 12 weeks.
OUTCOMES Primary outcome: In women with 16-week negative OGTT, GDM at 28 weeks
Description:
Aim: To evaluate the effect of a soluble fibre supplement in glucose metabolism in pregnant
women at high risk of developing gestational diabetes.
Study methodology: 12 week randomised, placebo-controlled, single-blinded study.
Intervention: Women will first be categorised according to their glycaemic status into two
groups: GDM and glucose tolerant women. Afterwards, each group will be randomised into two
groups and given either
1. Fibre supplement (Guar gum)
2. Placebo (Cellulose) The participants will take the dietary supplement three times a day
for 12 weeks. They will receive regular antenatal control according to NICE guidelines
recommendations. Compliance will be addressed by weekly phone calls.
Number of volunteers: The number of participants will be arbitrarily define as no data
of this type of intervention exists in this cohort. 40 participants will be recruited.
Previous studies, outside pregnancy, have observed metabolic effects in samples of 15-40
subjects.
Recruitment: Women will be recruited in the antenatal clinic at Queen Charlotte and
Chelsea's Hospital. An information sheet will be provided to eligible women in the first
antenatal visit to explain the purposes of the study. Women who decide to take part will
be asked to sign a consent form.
Randomisation: Initially women will be categorised according to glycaemic status in two
cohorts: Glucose tolerant and Early gestational diabetes (GDM) cohort. Each of the two
cohorts will then be independently randomised to either intervention or standard care
using the sealed envelope website. Guar gum (intervention) and cellulose (placebo) will
be provided in identical packed sachets.
PRIMARY OUTCOME MEASURES
- GDM at 28 weeks
- Glucose values at 0 and 120 minutes during an OGTT performed at 28 weeks in the
glucose tolerant group.
SECONDARY OUTCOME MEASURES
Assessing insulin sensitivity and insulin secretion at 28 weeks of pregnancy in the
glucose tolerant cohort of women through validated indices using glucose and insulin (or
C-peptide) values derived from the OGTT.
- Insulin sensitivity will be assessed using the Matsuda formula
- Insulin secretion will be assessed by second-void fasting UCPCR.
6. ASSESSMENT AND FOLLOW UP Women will be assessed by the researchers at four
different visits. At the first antenatal visit, the general care team will
mentioned the study, if the patient consents, she will then be approached by the
researchers to explain the study protocol. At the second visit, when the OGTT is
performed, women who decided to take part in the study will sign the consent from.
At the next antenatal visit where results from the OGTT are explained, women
included will be randomised. The last research visit will take place at 28 weeks
gestation. Additionally, they will be contacted weekly, by telephone to assess
compliance and confirm willingness to participate in the study.
1. st visit (≤16 weeks gestation) Women with a previous history of GDM will be
considered at high risk of recurrence and will be referred to the antenatal
clinic before 16 weeks of pregnancy. At this first visit, an information sheet
will be provided and women will have time to consider if they are willing to
participate and inform the research team at their next antenatal visit.
2. nd visit Women who decide to participate will inform the research team when
they attend their second antenatal visit, when an OGTT is to be performed. I
After the participants have agreed to take part in the study and consent has
been signed, data regarding anthropometrics, demographics and medical history
will be collected. This information will be obtained by reviewing the
participant's medical notes.
3. rd visit (Randomisation)
After obtaining the results from the OGTT, women will be categorised by their
glycaemic status and divided into two independent cohorts:
- Women diagnosed with gestational diabetes (according to NICE guidelines 2015
diagnostic criteria): early GDM cohort
- Women with normal glucose tolerance or impaired glucose tolerance but not
fulfilling GDM criteria: Glucose tolerant cohort.
Women from each cohort will be randomised into two groups after the results of the OGTT
are obtained:
- Intervention group: Guar gum fibre supplement
- Placebo group: Cellulose supplement Women will the fibre supplement 3 times a day
(with each main meal) until the 28th week of pregnancy when they will be
re-evaluated.
4rd visit (28th weeks gestation)
Glycaemic status will be assessed at 28 weeks gestation in the two cohorts of women
participating in the study:
- Women from the Glucose tolerant cohort will undergo a second OGTT.
- In women in the Early GDM cohort, glycaemic control will be assessed by the need of
insulin treatment (yes/no).
PROCEDURES Women will be advised to fast for 10 hours the night before the oral glucose
tolerance test. They will also be advised no to restrict carbohydrate ingestion the
three days prior to the OGTT. At the antenatal clinic, blood samples will be collected
at baseline (0 min) and at 120 min after the administration of an oral load of 75 g of
glucose.
Serum insulin and C-peptide will be collected at 0 and 120 min during the OGTT.
ASSESSMENTS
(i) Gestational diabetes Gestational diabetes will be diagnosed if fasting plasma
glucose >5.6 mmol/L and/or 120 min plasma glucose >7.8 mmol/L after the glucose load
administered in the OGTT. Women with fasting plasma glucose <5.6 mmol/L and 120 min
plasma glucose <7.8 mmol/L will be classified as "Glucose tolerant".
(ii) Insulin sensitivity Insulin sensitivity will be assessed using the Matsuda index as
originally described (18) (Equation 1) and using two modified Matsuda equations in which
insulin is substitute by either serum or urinary C-peptide (21,22) (Equations 2 and 3).
Equation 1. ISOGTT= 10,000 / √ {[FPG x fasting insulin] x [mean glucose x mean insulin
during OGTT]} Equation 2. ISOGTTC-pep=500,000/√{[FPGxFsC-pep] x [mean glucose x mean
sC-pep during the OGTT]} Equation 3. ISOGTT-UCPCR=500,000/√{[FPG×FUCPCR pmol/mmol] x
[mean glucose x mean UCPCR during the OGTT]}
(iii) Insulin secretion Insulin secretion will be estimated by the UCPCR obtained using
the fasting second-void urine sample, as it is strongly correlated with serum insulin,
serum C-peptide (19) and 24-h urinary C-peptide (20).
Insulin response will be estimated using the UCPCR calculated with 120 min post-OGTT
urine sample, as it is strongly correlated with the C-peptide and insulin area under the
curve (19).
(iv) Need of insulin treatment, Days to insulin treatment and Total insulin dose Medical
records of women in the Early GDM cohort will be review in order to determine the need
of insulin treatment (yes/no) at 28 weeks gestation.
WITHDRAWAL CRITERIA Participants will be free to withdraw at any time and are not
required to give a reason.
STATISTICS AND DATA ANALYSIS Data handling and analysis will be carried out by SPSS
version 20.0 version. No power calculation to decide sample size will be used. The
number of participants has been arbitrarily defined, as it is a pilot study. The study
aims to recruit 40 women.
In the Glucose tolerant women cohort:
For the primary outcome, GDM (yes/no), logistic regression analysis will be performed.
For the secondary outcomes, insulin sensitivity and insulin secretion, linear regression
analysis will be performed.
In the early GDM cohort:
For the primary outcome, need for insulin treatment (yes/no), logistic regression
analysis will be performed.
