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Trial registered on ANZCTR
Registration number
ACTRN12623000144617
Ethics application status
Approved
Date submitted
27/01/2023
Date registered
13/02/2023
Date last updated
13/02/2023
Date data sharing statement initially provided
13/02/2023
Type of registration
Prospectively registered
Titles & IDs
Public title
The choice effect on open label placebo for chronic pain
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Scientific title
The choice effect on open label placebo on pain intensity in adults with chronic pain: a randomized controlled trial
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Secondary ID [1]
308838
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None
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Universal Trial Number (UTN)
U1111-1287-4145
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Trial acronym
OPCP
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Linked study record
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Health condition
Health condition(s) or problem(s) studied:
Chronic Pain
328798
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Condition category
Condition code
Alternative and Complementary Medicine
325808
325808
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0
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Other alternative and complementary medicine
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Anaesthesiology
325918
325918
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0
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Pain management
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Intervention/exposure
Study type
Interventional
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Description of intervention(s) / exposure
Participants with chronic pain will be randomized to one of three groups: Choice, No Choice and Natural History. Participants randomized to Choice and No Choice groups will receive an open-label placebo (OLP) treatment and will be asked to use their treatment twice every day for two weeks. Those randomized to Natural History will not receive any treatment.
The Choice group will be given the opportunity to choose their OLP treatment between oral pills and nasal spray before the two-week treatment period and decide when to take each of two doses every day. The No Choice group will be assigned a OLP treatment by the researcher and must use the treatment once in the morning and once in the evening every day for two weeks.
Treatment adherence will be assessed by self-report after the two-week treatment period.
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Intervention code [1]
325282
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Treatment: Other
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Comparator / control treatment
The control group is a no-treatment Natural History control group.
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Control group
Active
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Outcomes
Primary outcome [1]
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Pain intensity assessed by Brief Pain inventory
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Assessment method [1]
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Timepoint [1]
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Baseline, 2 weeks post-initiating treatment
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Secondary outcome [1]
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Pain interference assessed by Brief pain inventory
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Assessment method [1]
417856
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Timepoint [1]
417856
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Baseline, 2 weeks post-initiating treatment
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Secondary outcome [2]
417857
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Perceived disability related to chronic pain, assessed using a modified version of Roland-Morris Disability Questionnaire where “back pain” will be replaced with “pain”
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Assessment method [2]
417857
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Timepoint [2]
417857
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Baseline, 2 weeks post-initiating treatment
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Secondary outcome [3]
417858
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Fear of movement or (re)injury, assessed using Tampa Scale of Kinesiophobia
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Assessment method [3]
417858
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Timepoint [3]
417858
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Baseline, 2 weeks post-initiating treatment
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Secondary outcome [4]
417859
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Depression, measured using the Depression Anxiety Stress Scales - 21 (DASS-21)
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Assessment method [4]
417859
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Timepoint [4]
417859
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Baseline, 2 weeks post-initiating treatment
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Secondary outcome [5]
417860
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Perceived effectiveness, convenience, side effects and overall satisfaction with the treatment will be measured using the Treatment Satisfaction Questionnaire for Medication – II (TSQM-II). The scores for each subscale will be summed to calculate a composite score ranging from 0 to 100, where a higher score indicating greater satisfaction with the treatment.
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Assessment method [5]
417860
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Timepoint [5]
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2 weeks post-initiating treatment
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Secondary outcome [6]
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Treatment adherence, assessed by asking participants “Over the past 14 days, on how many days did you take two placebo pills/use nasal spray twice?”
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Assessment method [6]
417861
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Timepoint [6]
417861
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2 weeks post-initiating treatment
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Secondary outcome [7]
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Evaluation of the effectiveness of the choice manipulation, assessed by asking participants in the OLP arms "How much choice do you feel you had over your treatment?” (1 = no choice at all; 10 =complete choice).
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Assessment method [7]
417862
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Timepoint [7]
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2 weeks post-initiating treatment
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Secondary outcome [8]
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Anxiety, measured using the Depression Anxiety Stress Scales - 21 (DASS-21)
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Assessment method [8]
418192
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Timepoint [8]
418192
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Baseline, 2 weeks post-initiating treatment
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Secondary outcome [9]
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Stress, measured using the Depression Anxiety Stress Scales - 21 (DASS-21)
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Assessment method [9]
418193
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Timepoint [9]
418193
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Baseline, 2 weeks post-initiating treatment
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Eligibility
Key inclusion criteria
• Age 18 and above
• Self-reported persistent pain on more days than not for at least three months
• Self-reported current pain intensity of moderate or greater severity (evidenced by a score of > 3 (/10) on a pain intensity numeric rating scale, PI-NRS).
• Willingness to provide written informed consent
• Willingness to participate and comply with the study protocol
• Fluent in English
• Competent to give consent
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Minimum age
18
Years
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Maximum age
No limit
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Sex
Both males and females
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Can healthy volunteers participate?
No
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Key exclusion criteria
• Current serious illness that requires therapy, where pain is not the primary symptom
• Serious psychiatric illness (e.g., bipolar disorder, schizophrenia)
• Drug or alcohol addiction
• Currently pregnant
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Study design
Purpose of the study
Treatment
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Allocation to intervention
Randomised controlled trial
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Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central randomisation by computer
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Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Quasi-randomisation allocation: . Participants will be allocated to one of the three conditions on a 2:2:1 ratio in a quasi-random fashion according to the time of recruitment. Group allocation will be done in blocks of 3 with the first participant randomly assigned to receive Choice or Natural History. Choice involves a choice between one of two types of OLP treatment (oral pill or nasal spray) to use for the treatment period and a choice over when they use their twice-daily treatment every day. Natural history involves receiving no treatment. If the first participant is randomised to the Choice group, then the next participant is randomised to one of the remaining two conditions, i.e. either Natural History or No Choice. If the first participant is allocated to Natural History, then the second participant is automatically allocated to the Choice group, such that the No Choice participant always follows the Choice participant. This is necessary to allow the No Choice group to have their treatment yoked to the Choice group, such that the No Choice participant in a given block receives whichever OLP treatment the Choice participant chooses. This allows us to balance the types of OLP across the Choice and No Choice group. The final participant in the triad is allocated to whichever treatment remains out of Natural History and No Choice. Randomization will be stratified by gender and whether participants currently experience moderate pain (less or equal to 5 out of 10) or severe pain (greater than 5 out of 10) assessed using the pain intensity NRS in the screening questionnaire.
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Masking / blinding
Open (masking not used)
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Who is / are masked / blinded?
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Intervention assignment
Parallel
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Other design features
Not Applicable
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Phase
Not Applicable
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Type of endpoint/s
Efficacy
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Statistical methods / analysis
We powered the study based on a 1-point difference between OLP and Natural History with estimates of standard deviation derived from Kleine-Borgmann et al (2019) of 1.82 and 1.31, respectively. Using a 2:1 allocation ratio for No Choice: Natural History, power analysis indicated that 122 (81 No Choice and 41 Natural History) participants would be required to detect such an effect with 90% power and alpha=.05. Applying the same logic to the Choice vs No Choice comparison and an equal allocation ratio, we would require 142 (72 per OLP group) to achieve 90% power to detect such an effect with alpha=.05. Therefore we aimed to recruit 205 participants with a 2:2:1 ratio of Choice: No Choice: Natural History to achieve at least 90% power across all comparisons. This equates to 82, 82, and 41 participants in the Choice, No Choice and Natural History arms.
For the primary outcome, intention-to-treat (ITI) analysis will be used to compare the effect of Choice, No Choice and Natural History on pain intensity. The primary endpoint (mean scores on the pain intensity subscale of the BPI at post-treatment) will be assessed using a multilevel model with group (Choice, No Choice, Natural History) and baseline pain intensity scores included as factors. A sensitivity analysis will be conducted using a per-protocol approach as a secondary analysis. It will include only participants who complete the study.
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Recruitment
Recruitment status
Not yet recruiting
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Date of first participant enrolment
Anticipated
1/04/2023
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Actual
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Date of last participant enrolment
Anticipated
1/12/2023
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Actual
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Date of last data collection
Anticipated
15/12/2023
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Actual
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Sample size
Target
205
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Accrual to date
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Final
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Recruitment in Australia
Recruitment state(s)
NSW
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Funding & Sponsors
Funding source category [1]
313063
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University
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Name [1]
313063
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The University of Sydney
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Address [1]
313063
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School of Psychology, A18
University of Sydney
NSW 2006
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Country [1]
313063
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Australia
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Primary sponsor type
University
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Name
The University of Sydney
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Address
University of Sydney
NSW 2006
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Country
Australia
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Secondary sponsor category [1]
314752
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None
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Name [1]
314752
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Address [1]
314752
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Country [1]
314752
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Ethics approval
Ethics application status
Approved
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Ethics committee name [1]
312314
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The University of Sydney Human Research Ethics Committee
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Ethics committee address [1]
312314
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University of Sydney
NSW 2006
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Ethics committee country [1]
312314
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Australia
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Date submitted for ethics approval [1]
312314
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11/01/2022
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Approval date [1]
312314
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07/10/2022
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Ethics approval number [1]
312314
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2022/342
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Summary
Brief summary
Converging evidence has shown that treatment choice can enhance the deceptive placebo effect for a range of conditions, such as pain. The current study aims to test whether treatment choice can facilitate the effect of open-label placebo (OLP) on chronic pain in a randomized controlled trial. Participants will be randomized to one of the three conditions: Choice, No Choice and Natural History. Both Choice and No Choice will receive OLP treatment and use their OLP treatment twice every day for two weeks while Natural History will not receive any treatment. Critically, the Choice group will be given the opportunity to choose a treatment between two options and decide when to use their treatment every day, whereas the No Choice group will be assigned a treatment and must use their treatment once in the morning and once in the evening. We hypothesize that (1) OLP will reduce chronic pain relative to Natural History; (2) choice over OLP treatment will enhance the OLP effect relative to No Choice.
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Trial website
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Trial related presentations / publications
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Public notes
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Contacts
Principal investigator
Name
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Prof Ben Colagiuri
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Address
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A19 - Griffith Taylor
The University of Sydney
NSW 2006 Australia
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Country
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Australia
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Phone
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+61 2 93514589
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Fax
124214
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Email
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[email protected]
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Contact person for public queries
Name
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Prof Ben Colagiuri
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Address
124215
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A19 - Griffith Taylor
The University of Sydney
NSW 2006 Australia
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Country
124215
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Australia
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Phone
124215
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+61 2 93514589
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Fax
124215
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Email
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[email protected]
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Contact person for scientific queries
Name
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Prof Ben Colagiuri
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Address
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A19 - Griffith Taylor
The University of Sydney
NSW 2006 Australia
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Country
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Australia
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Phone
124216
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+61 2 93514589
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Fax
124216
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Email
124216
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[email protected]
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Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
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What data in particular will be shared?
De-identified participant data collected during the trial.
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When will data be available (start and end dates)?
Immediately following publication of study results with no end date determined.
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Available to whom?
Researchers providing a methodologically and ethically sound proposal.
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Available for what types of analyses?
Any types of analyses.
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How or where can data be obtained?
Data can be obtained by contacting the principal investigator, Prof Ben Colagiuri at
[email protected]
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What supporting documents are/will be available?
No Supporting Document Provided
Doc. No.
Type
Citation
Link
Email
Other Details
Attachment
18149
Study protocol
[email protected]
18150
Statistical analysis plan
[email protected]
18151
Analytic code
[email protected]
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.
Download to PDF