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Trial registered on ANZCTR

Registration number

ACTRN12619001397101

Ethics application status

Approved

Date submitted

7/09/2019

Date registered

14/10/2019

Date last updated

5/03/2021

Date data sharing statement initially provided

14/10/2019

Type of registration

Prospectively registered

Titles & IDs

Public title

The effects of reducing insulin versus eating carbohydrates on glycaemic control and performance with aerobic exercise in type 1 diabetes

Scientific title

The effects of reducing insulin versus eating carbohydrates on glycaemic control and performance with aerobic exercise in type 1 diabetes.

Secondary ID [1]

Nil Known

Universal Trial Number (UTN)

U1111-1239-6201

Trial acronym

Linked study record

Health condition

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

Type 1 Diabetes

Condition category

Condition code

Diet and Nutrition

Other diet and nutrition disorders

Metabolic and Endocrine

Diabetes

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

25 Male Participants (in groups of 5 participants at a time) will be performing a walking exercise for 45 mins on a standardized treadmill at a 1% gradient. The brisk walk will be determined by participants trying to maintain the speed of 7.24 kilometers per hour throughout the entire 45 min. Following the aerobic exercise, participants will perform a six-minute walk test which is a validated measure of predicted VO2 max and will serve as a performance test. This will be followed by a 7 days washout period and then the same group of participants will be repeating the above process for the crossover treatment.

Ninety minutes before the exercise all participants on continuous subcutaneous insulin infusion (CSII; known as insulin pump therapy) will start a 50% temporary basal rate reduction as per guidelines.

Sixty minutes before the exercise, all participants will eat a carbohydrate predominant mixed meal individualized to contain 0.66 g of carbohydrate/kg of body and 3.375 kcal/kg of body weight, meeting the requirements of both energy expenditure and exercise carbs guidelines

Participants in the reduced insulin group will administer 50% of their normal prandial dose of insulin immediately before the meal as a single bolus, with no combo or dual wave boluses allowed. Participants in the exercise carbs group will not administer any prandial insulin or adjust the doses of their basal insulin.

The first meal post exercise will be a pre-prepared lunch of sandwiches and fruit (equivalent to 1 g of carbohydrate/kg of body weight) will be provided.

Each patient will be provided with a Freestyle Libre reader and sensor to allow interstitial glucose levels to be measured by Flash Glucose Monitor (FGM) throughout the study period. The sensor will be inserted at least 36-48 hours before exercise day to ensure accurate calibration. Due to concerns over a several minute lag between changes in interstitial and blood glucose levels, Capillary Blood Glucose, Ketone and lactate levels will be measured on a calibrated glucometer at baseline and every 15 minutes whilst exercising as well as at baseline, at the completion of the aerobic exercise, and following completion of the 6-min walk test.

All treatment decisions will be based on CBG levels and not on FGM and will be administered by the research team in presence of a medical professional (Endocrinologist). All participants data of food intake will be recorded in a case record form for the night before, day of, and for the 48 hours following the study with the details of all meals, snacks and water consumed on a regular basis. Outside of these time frames, they will be allowed to consume their normal diets and there will be no strict and restrictive diet guidelines.

Intervention code [1]

Treatment: Other

Comparator / control treatment

Comparator Intervention - Insulin reduction.

Ninety minutes before the exercise all participants on continuous subcutaneous insulin infusion (CSII; known as insulin pump therapy) will start a 50% temporary basal rate reduction as per guidelines.

Participants in the reduced insulin group will administer 50% of their normal prandial dose of insulin immediately before the meal as a single bolus, with no combo or dual wave boluses allowed.

Control group

Active

Outcomes

Primary outcome [1]

The composite primary outcomes of the study are the time of glucose levels in target range (4-10 mmol/L), the time of glucose levels in hypoglycaemia (<4.0 mmol/L), the time of glucose levels in hyperglycaemia ( > 10.0 mmol/L). Both the outcomes will be assessed by measuring the capillary blood glucose using a glucometer and further assessed by laboratory assay of blood sample.

Timepoint [1]

Monitored from the start of the exercise day (baseline), during (every 15 minutes of the exercise) and in the four hours following 45 minutes of aerobic exercise.

Secondary outcome [1]

The composite secondary outcome is the effects on capillary Ketone and lactate levels.
Ketone and blood lactate as assessed by laboratory assay of blood sample.

Timepoint [1]

Monitored from the start of the exercise day (baseline), during (every 15 minutes of the exercise) and in the four hours following 45 minutes of aerobic exercise.

Secondary outcome [2]

The effects on predicted VO2 max as a marker of performance as assessed using the 6 minute walk test and using a heart rate monitor

Timepoint [2]

Monitored from the start of the exercise day (baseline), during and in the four hours following 45 minutes of aerobic exercise.

Eligibility

Key inclusion criteria

Patients diagnosed with type 1 diabetes (T1D).
T1D Men (but not on testosterone replacement therapy)
Patients competent at self-management of all diabetes tasks
T1D patients who have an HbA1c of 45 - 90 mmol/mol (within the last 3 months)
T1D patients who are able to walk unaided for 45 mins at a fast pace (7 km/h)
T1D patients on treatment with a traditional insulin pump therapy

Minimum age

18 Years

Maximum age

60 Years

Sex

Males

Can healthy volunteers participate?

Key exclusion criteria

Type 1 diabetes (T1D) patients with any co-morbidity that could make exercise unsafe (e.g. inter-current illness, cardiovascular disease, cerebrovascular disease, severe diabetic retinopathy, nephropathy or neuropathy)
T1D patients who are currently on treatment with medications that alter heart rate (e.g. beta blockers)
T1D patients with closed or semi-closed loop insulin therapy

Study design

Purpose of the study

Prevention

Allocation to intervention

Randomised controlled trial

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

Allocation is not concealed

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

Simple randomization using a randomization table created by computer software (i.e. computerized sequence generation)

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Crossover

Other design features

This is a randomized, cross-over design study where up to 20 men with T1D will be asked to complete two sessions to explore how reducing insulin versus eating carbohydrates compare for maintaining euglycemia and affecting performance around aerobic exercise. This study will initially only be undertaken in men to minimize any hormonal influences on glycaemic control.

Participants will be recruited through the Waikato Regional Diabetes Service (WRDS), and will initially be contacted by a member of the WRDS (letter, phone call, text or email) asking them if they are interested to participate. A participant information sheet will also be provided at this time.

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

We expect this study to be adequately powered given smaller studies with less than 10 participants have shown significant differences in glucose levels. Repeated measures ANOVA’s will be performed using SPSS to compare time in normoglycaemia (primary outcome) and time in hyperglycaemia, capillary Ketone and lactate levels, and VO2 max (secondary outcomes). Chi-square tests will be performed to determine whether there are any differences in episodes of hypoglycaemia between the two groups. No analysis will be initiated prior to all data being collected and significance will be defined as a P value < 0.05.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

14/10/2019

Actual

14/11/2019

Date of last participant enrolment

Anticipated

11/11/2019

Actual

10/02/2020

Date of last data collection

Anticipated

28/02/2020

Actual

2/03/2020

Sample size

Target

Accrual to date

Final

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Waikato

Funding & Sponsors

Funding source category [1]

University

Name [1]

University of Waikato

Address [1]

University of Waikato, Hillcrest, Hamilton, Waikato, New Zealand, 3216

Country [1]

New Zealand

Primary sponsor type

University

Name

University of Waikato

Address

University of Waikato, Department of Health, Sport and Human Performance
Hillcrest, Hamilton, Waikato, New Zealand 3216

Country

New Zealand

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Health and disability ethics committees (HDEC)

Ethics committee address [1]

Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

09/10/2019

Approval date [1]

30/10/2019

Ethics approval number [1]

19/NTB/175

Summary

Brief summary

Exercise is a cornerstone of management in type 1 diabetes (T1D) because of the improvement in glycemic control, reduction in cardiovascular disease and increased quality of life. However, the majority of patients with T1D do not meet their exercise requirements due to either the fear or risk of hypoglycaemia. To reduce these barriers, two consensus guidelines have been published that have contrasting approaches with either reducing the doses of insulin before exercise or eating additional carbohydrates. Importantly, these guidelines are predominantly based on expert opinion or laboratory-based studies of less than 10 participants. Furthermore, there are no published studies investigating which approach is more effective at controlling glucose levels around exercise, including whether there are any deleterious effects on performance from hyperglycaemia and/or ketonaemia and/or lactataemia. This study aims to answer these questions in a real-world setting, which will provide patients with T1D and their health professionals evidence-based advice for the best management of their diabetes around exercise.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Ryan Paul

Address

Diabetes / Endocrinology, Waikato District Health Board Private Bag 3200, Pembroke St, Hamilton 3240

Country

New Zealand

Phone

+64 021 310974

Fax

ryan.paul@waikatodhb.health.nz

Contact person for public queries

Name

Varun Ramesh Vartak

Address

University of Waikato, Hillcrest, Hamilton, Waikato New Zealand 3216

Country

New Zealand

Phone

+64 022 5220014

Fax

varun.r.vartak@gmail.com

Contact person for scientific queries

Name

Lynne Chepulis

Address

University of Waikato, Research and Enterprise Department, Hillcrest, Hamilton, Waikato, New Zealand, 3216

Country

New Zealand

Phone

+64 022 6753353

Fax

lynnec@waikato.ac.nz

Data sharing statement

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

No/undecided IPD sharing reason/comment

The data will not be made available as the study will be taking informed consent from every individual participant who will be a type 1 diabetes patient to not disclose or share any data, information with any other individual, organization without prior approval and thus, only post the approval of the individual participant, it would be possible to arrange for the data to be made available for sharing. Else it will not be shared with anyone.

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

Source	Title	Year of Publication	DOI
Embase	Comparing Two Treatment Approaches for Patients with Type 1 Diabetes During Aerobic Exercise: a Randomised, Crossover Study.	2021	https://dx.doi.org/10.1186/s40798-021-00319-5

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

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Documents added manually

Documents added automatically