ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12611000488909

Ethics application status

Approved

Date submitted

9/05/2011

Date registered

10/05/2011

Date last updated

7/04/2014

Type of registration

Prospectively registered

Titles & IDs

Public title

The role of Vitamin C in managing type 2 diabetes: Vitamin C, Thiazolidinediones and their combined effect on
Adiponectin

Scientific title

People with Type 2 diabetes currently treated with thiazolidinediones supplemented with Vitamin C and the combined effect on adiponectin as a therapeutic for metabolic disease.

Secondary ID [1]

Nil

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

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

Type 2 diabetes

Condition category

Condition code

Metabolic and Endocrine

Diabetes

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Dose escalation of Vitamin C supplementation, twice daily oral tablets, (500, 1000, 1500 and 2000 mg) for two weeks at each dose with no washout period in between. Vitamin C supplementation will be taken in addition to participants' existing thiazolidinedione treatment which will continue as usual.

Intervention code [1]

Treatment: Other

Comparator / control treatment

None

Control group

Uncontrolled

Outcomes

Primary outcome [1]

Increase in high molecular weight adiponectin assessed using a blood test and subsequent laboratory analysis of the sample.

Timepoint [1]

At the start of the trial, fortnightly after each increase in Vitamin C dosage and then a fortnight after the final Vitamin C dosage is complete.

Secondary outcome [1]

Nil

Timepoint [1]

Nil

Eligibility

Key inclusion criteria

Female or male participants between the ages of 18 and 70 with non insulin dependent type 2 diabetes under TZD treatment (either rosiglitazone 4 – 8 mg or piogitazone greater than or equal 30 mg) with or without metformin.
HbA1C level 7 – 8.5 %.
Participant on stable diabetic therapy for three months prior to the intervention.

Minimum age

18 Years

Maximum age

70 Years

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

HbA1C level greater than 8.5 %
Participants must have a stable body weight (< 5% selfreported weight loss/gain) within last 3 months prior to enrolment.
Participants taking iron supplements.

Study design

Purpose of the study

Treatment

Allocation to intervention

Non-randomised 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

Who is / are masked / blinded?

Intervention assignment

Other design features

Phase

Type of endpoint/s

Efficacy

Statistical methods / analysis

Recruitment

Recruitment status

Recruiting

Date of first participant enrolment

Anticipated

10/05/2011

Actual

18/11/2011

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)

Funding & Sponsors

Funding source category [1]

Government body

Name [1]

Queensland Department of Employment, Economic Development and Innovation

Address [1]

Queensland Government
PO Box 15168, City East, Qld, 4002

Country [1]

Australia

Primary sponsor type

Hospital

Name

Princess Alexandra Hospital

Address

199 Ipswich Road Woolloongabba, Brisbane, Queensland, 4102

Country

Australia

Secondary sponsor category [1]

University

Name [1]

University of Queensland

Address [1]

The University of Queensland
Brisbane QLD 4072 Australia

Country [1]

Australia

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Metro South Health Service District Human Research Ethics Committee (EC00167)

Ethics committee address [1]

Centres for Health Research Level 2, Building 35
Princess Alexandra Hospital
Ispwich Road WOOLLOONGABBA QLD 4102

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

Approval date [1]

21/04/2011

Ethics approval number [1]

EC00167

Summary

Brief summary

Thiazolidinediones (TZD) are a class of drug commonly prescribed to manage type 2 diabetes. While the exact
mechanism of action is unknown, efficacy of the drug is closely correlated with improved circulating concentration of
a protein, adiponectin, secreted by fat tissue. Adiponectin is decreased in many diseases states including type 2
diabetes. Adiponectin is secreted as multimers of different sizes, termed low molecular weight (LMW) and high
molecular weight (HMW), and while an increase in circulating adiponectin is beneficial, it is more specifically an
increase in the HMW multimers that is correlated with improvement in health. An improvement in adiponectin profile refers to an increase in the proportion of the multimers present as HMW and may also be concomitant with an increase in total adiponectin.

Previous studies have demonstrated that high dose Vitamin C alone can improve glucose control in obese and
diabetic patients. Researchers involved with the proposed research project have demonstrated that combining
Vitamin C with TZD treatment has a synergistic effect on adiponectin profile in vitro in a human adipose cell line.
Vitamin C alone improves adiponectin profile 1.7 fold, while improvements are 5 fold over baseline when in
combination with TZD. Combining the evidence from previous studies and these in vitro observations
demonstrates a potential for combining TZD with high dose Vitamin C to get an improved treatment for managing
type 2 diabetes.

Research Design and Methods: Patients will have a two week wash out period to control vitamin c levels, and then
two weekly intervals on escalating doses of oral vitamin C for 8 weeks (4 doses, 500 mg / day, 1000 mg / day, 1500
mg / day and 2000 mg / day). Each patient will serve as their own control, with assessment of total and HMW
adiponectin at the beginning and end of the trial and at dose escalation points in between as primary endpoints.
Other indicators of improvement in metabolic parameters will also be monitored.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

A/Prof Anthony Russell

Address

Department of Diabetes and Endocrinology, Ground Floor Building 1, Princess Alexandra Hospital 199 Ipswich Road Woolloongabba QLD 4102

Country

Australia

Phone

+61 7 3240 5914

Fax

a.russell@uq.edu.au

Contact person for public queries

Name

Associate Professor Anthony Russell

Address

Department of Diabetes and Endocrinology, Ground Floor
Building 1, Princess Alexandra Hospital
199 Ipswich Road
Woolloongabba QLD 4102

Country

Australia

Phone

+61 7 3240 5914

Fax

a.russell@uq.edu.au

Contact person for scientific queries

Name

Associate Professor Anthony Russell

Address

Department of Diabetes and Endocrinology, Ground Floor
Building 1, Princess Alexandra Hospital
199 Ipswich Road
Woolloongabba QLD 4102

Country

Australia

Phone

+61 7 3240 5914

Fax

a.russell@uq.edu.au

No information has been provided regarding IPD availability

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

No additional documents have been identified.

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Documents added manually

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