Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12625000691448
Ethics application status
Approved
Date submitted
11/06/2025
Date registered
30/06/2025
Date last updated
30/06/2025
Date data sharing statement initially provided
30/06/2025
Type of registration
Prospectively registered

Titles & IDs
Public title
Identifying the best way to monitor blood sugar levels in people with diabetes after a heart or lung transplant
Scientific title
Effect of continuous versus point-of-care glucose monitoring on glycaemic control and hypoglycaemia in patients with insulin requiring diabetes after heart or lung transplantation
Secondary ID [1] 314630 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
diabetes mellitus 337775 0
heart transplant 337776 0
lung transplant 337777 0
Condition category
Condition code
Metabolic and Endocrine 334099 334099 0 0
Diabetes
Cardiovascular 334100 334100 0 0
Other cardiovascular diseases
Respiratory 334101 334101 0 0
Other respiratory disorders / diseases

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
During the study, participants will complete 8-weeks of continuous glucose monitoring using the Freestyle Libre2+ and Freestyle Libre PRO iQ glucose monitoring systems. Devices will be applied to the back of the non-dominant arm as per manufacturer's instructions using the sensor applicator. The process is painless.

In one 4-week period participants will be able to see their glucose levels in real-time and adjust insulin dosing and food intake accordingly (Libre 2+). During the other 4-week period, participants will be blinded to continuous glucose monitoring and be required to monitor their glucose levels in the usual fashion using fingerprick capillary blood and point-of-care glucometer testing (Libre PRO iQ). Adherence will be measured using the LibreLink associated mobile phone application, which records "time worn" for each sensor based on the time glucose levels are being recorded during a standard 14-day wear.

The order in which participants complete the blinded and unblinded phases of continuous glucose monitoring will be allocated randomly. There is no washout period between the two sensor phases, and phase 2 will immediately follow phase 1.
Intervention code [1] 331250 0
Treatment: Devices
Comparator / control treatment
Participants will serve as their own control in this cross-over trial. For within subject comparisons, phase 1 data accumulated during weeks 3-4 will be compared to phase 2 data collected during weeks 7-8 to assess our pre-specified primary and secondary outcome measures. Weeks 1-2 and weeks 5-6 will be considered run-in periods for participants to become acclimatized to the blinded (PRO iQ) or unblinded (Libre 2+) sensors.
Control group
Active

Outcomes
Primary outcome [1] 341768 0
Continuous glucose monitoring measured time in range
Timepoint [1] 341768 0
Outcome will be assessed following completion of both study phases. Phase 1 and phase 2 are assigned at random. Phase 1 encompasses a 4-week wear of the blinded (PRO iQ) sensor. Phase 2 encompasses a 4-week wear of the unblinded (Libre 2+) sensor.
Secondary outcome [1] 448633 0
Continuous glucose monitoring measured time below range
Timepoint [1] 448633 0
Outcome will be assessed following completion of both study phases. Phase 1 and phase 2 are assigned at random. Phase 1 encompasses a 4-week wear of the blinded (PRO iQ) sensor. Phase 2 encompasses a 4-week wear of the unblinded (Libre 2+) sensor.
Secondary outcome [2] 448634 0
Continuous glucose monitoring measured glycaemic variability
Timepoint [2] 448634 0
Outcome will be assessed following completion of both study phases. Phase 1 and phase 2 are assigned at random. Phase 1 encompasses a 4-week wear of the blinded (PRO iQ) sensor. Phase 2 encompasses a 4-week wear of the unblinded (Libre 2+) sensor.
Secondary outcome [3] 448635 0
Continuous glucose monitoring measured 14-day mean glucose
Timepoint [3] 448635 0
Outcome will be assessed following completion of both study phases. Phase 1 and phase 2 are assigned at random. Phase 1 encompasses a 4-week wear of the blinded (PRO iQ) sensor. Phase 2 encompasses a 4-week wear of the unblinded (Libre 2+) sensor.
Secondary outcome [4] 448636 0
Continuous glucose monitoring measured estimated HbA1c
Timepoint [4] 448636 0
Outcome will be assessed following completion of both study phases. Phase 1 and phase 2 are assigned at random. Phase 1 encompasses a 4-week wear of the blinded (PRO iQ) sensor. Phase 2 encompasses a 4-week wear of the unblinded (Libre 2+) sensor.
Secondary outcome [5] 448637 0
Continuous glucose monitoring measured time above range
Timepoint [5] 448637 0
Outcome will be assessed following completion of both study phases. Phase 1 and phase 2 are assigned at random. Phase 1 encompasses a 4-week wear of the blinded (PRO iQ) sensor. Phase 2 encompasses a 4-week wear of the unblinded (Libre 2+) sensor.

Eligibility
Key inclusion criteria
a) Age greater than 18 years.
b) Diagnosis of diabetes mellitus.
c) Treatment with subcutaneous insulin (greater than 10 units per day).
d) Stable insulin dose for at least 6 weeks prior to study enrolment.
e) More than 1-year since heart or lung transplant
Minimum age
18 Years
Maximum age
85 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
a) Current or recent continuous glucose monitor use (within 3 months of enrolment).
b) Recent organ rejection (within 6 months of enrolment) or unstable immuno-suppression doses (within 3 months of enrolment).
c) Vitamin C supplementation with doses greater than 500 mg per day.

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)
No
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table from a statistic book
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
Trials of continuous glucose monitoring (CGM) in patients with T2DM result in a 6% mean increase time in range and decreases in time above range, time below range, and HbA1c. This small-scale study will assess whether similar effect sizes are observed in patients with post-transplant diabetes and be used to assess the feasibility of a larger trial. The study population will consist of 30 patients and use a cross-over design with each patient acting as their own control.

The order of blinded versus unblinded CGM use will be randomised to prevent bias, although from clinical experience we feel it is unlikely as most patients do not increase standard fingerprick monitoring following completion of a period of continuous glucose monitoring (unpublished observations). To control for this potential confounding effect, the study is randomized, with 50% of participants starting with use of the blinded sensor, and the other 50% starting with the unblinded sensor. If there is a significant difference in results between the two groups during the blinded sensor period, statistical methods can be employed to adjust for the confounding effects of treatment sequence. As a pilot study, outcomes are not specifically hypothesis driven but intended to assess the effect size of the FreeStyle Libre2+ CGM intervention, making formal power analyses unjustified.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/07/2025
Actual
Date of last participant enrolment
Anticipated
1/05/2026
Actual
Date of last data collection
Anticipated
1/07/2026
Actual
Sample size
Target
30
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 28036 0
St Vincent's Hospital (Darlinghurst) - Darlinghurst
Recruitment postcode(s) [1] 44240 0
2010 - Darlinghurst

Funding & Sponsors
Funding source category [1] 319191 0
Charities/Societies/Foundations
Name [1] 319191 0
St Vincent's Clinic Research Foundation
Country [1] 319191 0
Australia
Primary sponsor type
Hospital
Name
St Vincent's Hospital, Sydney
Address
Country
Australia
Secondary sponsor category [1] 321658 0
None
Name [1] 321658 0
Address [1] 321658 0
Country [1] 321658 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 317773 0
St Vincent’s Hospital Human Research Ethics Committee
Ethics committee address [1] 317773 0
Ethics committee country [1] 317773 0
Australia
Date submitted for ethics approval [1] 317773 0
07/04/2025
Approval date [1] 317773 0
21/05/2025
Ethics approval number [1] 317773 0
2025/ETH00521

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 142098 0
Dr Christopher Alan Muir
Address 142098 0
Department of Endocrinology, St Vincent's Hospital, 390 Victoria Street, Darlinghurst, NSW 2010
Country 142098 0
Australia
Phone 142098 0
+61 4 5013 3265
Fax 142098 0
Email 142098 0
[email protected]
Contact person for public queries
Name 142099 0
Christopher Muir
Address 142099 0
Department of Endocrinology, St Vincent's Hospital, 390 Victoria Street, Darlinghurst, NSW 2010
Country 142099 0
Australia
Phone 142099 0
+61 2 8382 2622
Fax 142099 0
Email 142099 0
[email protected]
Contact person for scientific queries
Name 142100 0
Christopher Muir
Address 142100 0
Department of Endocrinology, St Vincent's Hospital, 390 Victoria Street, Darlinghurst, NSW 2010
Country 142100 0
Australia
Phone 142100 0
+61 2 8382 2622
Fax 142100 0
Email 142100 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No


What supporting documents are/will be available?

TypeCitationLinkEmailOther DetailsAttachment
Study protocol    PTDM CGM Study - study protocol, version 1.1, 08.05.2025.docx
Informed consent form    PTDM CGM Study - piscf, version 1.1, 08.05.2025.docx
Ethical approval    HREC approval.pdf


Results publications and other study-related documents

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

Documents added automatically
No additional documents have been identified.