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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
Scientific title
The choice effect on open label placebo on pain intensity in adults with chronic pain: a randomized controlled trial
Secondary ID [1] 308838 0
None
Universal Trial Number (UTN)
U1111-1287-4145
Trial acronym
OPCP
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Chronic Pain 328798 0
Condition category
Condition code
Alternative and Complementary Medicine 325808 325808 0 0
Other alternative and complementary medicine
Anaesthesiology 325918 325918 0 0
Pain management

Intervention/exposure
Study type
Interventional
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.
Intervention code [1] 325282 0
Treatment: Other
Comparator / control treatment
The control group is a no-treatment Natural History control group.
Control group
Active

Outcomes
Primary outcome [1] 333651 0
Pain intensity assessed by Brief Pain inventory
Timepoint [1] 333651 0
Baseline, 2 weeks post-initiating treatment
Secondary outcome [1] 417856 0
Pain interference assessed by Brief pain inventory
Timepoint [1] 417856 0
Baseline, 2 weeks post-initiating treatment
Secondary outcome [2] 417857 0
Perceived disability related to chronic pain, assessed using a modified version of Roland-Morris Disability Questionnaire where “back pain” will be replaced with “pain”
Timepoint [2] 417857 0
Baseline, 2 weeks post-initiating treatment
Secondary outcome [3] 417858 0
Fear of movement or (re)injury, assessed using Tampa Scale of Kinesiophobia
Timepoint [3] 417858 0
Baseline, 2 weeks post-initiating treatment
Secondary outcome [4] 417859 0
Depression, measured using the Depression Anxiety Stress Scales - 21 (DASS-21)
Timepoint [4] 417859 0
Baseline, 2 weeks post-initiating treatment
Secondary outcome [5] 417860 0
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.
Timepoint [5] 417860 0
2 weeks post-initiating treatment
Secondary outcome [6] 417861 0
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?”
Timepoint [6] 417861 0
2 weeks post-initiating treatment
Secondary outcome [7] 417862 0
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).
Timepoint [7] 417862 0
2 weeks post-initiating treatment
Secondary outcome [8] 418192 0
Anxiety, measured using the Depression Anxiety Stress Scales - 21 (DASS-21)
Timepoint [8] 418192 0
Baseline, 2 weeks post-initiating treatment
Secondary outcome [9] 418193 0
Stress, measured using the Depression Anxiety Stress Scales - 21 (DASS-21)
Timepoint [9] 418193 0
Baseline, 2 weeks post-initiating treatment

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
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
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

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)
Central randomisation by computer
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.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Not Applicable
Phase
Not Applicable
Type of endpoint/s
Efficacy
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.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/04/2023
Actual
Date of last participant enrolment
Anticipated
1/12/2023
Actual
Date of last data collection
Anticipated
15/12/2023
Actual
Sample size
Target
205
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 313063 0
University
Name [1] 313063 0
The University of Sydney
Country [1] 313063 0
Australia
Primary sponsor type
University
Name
The University of Sydney
Address
University of Sydney
NSW 2006
Country
Australia
Secondary sponsor category [1] 314752 0
None
Name [1] 314752 0
Address [1] 314752 0
Country [1] 314752 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 312314 0
The University of Sydney Human Research Ethics Committee
Ethics committee address [1] 312314 0
University of Sydney
NSW 2006
Ethics committee country [1] 312314 0
Australia
Date submitted for ethics approval [1] 312314 0
11/01/2022
Approval date [1] 312314 0
07/10/2022
Ethics approval number [1] 312314 0
2022/342

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.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 124214 0
Prof Ben Colagiuri
Address 124214 0
A19 - Griffith Taylor
The University of Sydney
NSW 2006 Australia
Country 124214 0
Australia
Phone 124214 0
+61 2 93514589
Fax 124214 0
Email 124214 0
ben.colagiuri@sydney.edu.au
Contact person for public queries
Name 124215 0
Prof Ben Colagiuri
Address 124215 0
A19 - Griffith Taylor
The University of Sydney
NSW 2006 Australia
Country 124215 0
Australia
Phone 124215 0
+61 2 93514589
Fax 124215 0
Email 124215 0
ben.colagiuri@sydney.edu.au
Contact person for scientific queries
Name 124216 0
Prof Ben Colagiuri
Address 124216 0
A19 - Griffith Taylor
The University of Sydney
NSW 2006 Australia
Country 124216 0
Australia
Phone 124216 0
+61 2 93514589
Fax 124216 0
Email 124216 0
ben.colagiuri@sydney.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
De-identified participant data collected during the trial.
When will data be available (start and end dates)?
Immediately following publication of study results with no end date determined.
Available to whom?
Researchers providing a methodologically and ethically sound proposal.
Available for what types of analyses?
Any types of analyses.
How or where can data be obtained?
Data can be obtained by contacting the principal investigator, Prof Ben Colagiuri at ben.colagiuri@sydney.edu.au.


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
18149Study protocol  ben.colagiuri@sydney.edu.au
18150Statistical analysis plan  ben.colagiuri@sydney.edu.au
18151Analytic code  ben.colagiuri@sydney.edu.au



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.