Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12625001025426
Ethics application status
Approved
Date submitted
26/08/2025
Date registered
16/09/2025
Date last updated
16/09/2025
Date data sharing statement initially provided
16/09/2025
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effect of Multiple Suggested Care Alternatives on Decision-Making in Primary Care Physicians
Scientific title
Determining the effect of presenting two or more appropriate treatment alternatives to primary care physicians, compared to one alternative, on care decisions.
Secondary ID [1] 315230 0
OSF Pre-registration: doi.org/10.17605/OSF.IO/GBDTE
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Musculoskeletal conditions 338683 0
Condition category
Condition code
Public Health 334969 334969 0 0
Health service research

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Physician participants were presented with two management plans for clinical scenarios commonly seen in primary care. Each scenario – one about a surgery referral for hip osteoarthritis, one on opioid prescribing for low-back pain – involved a decision about whether to remain with an existing management plan or to select an alternate plan. In the intervention condition physicians could receive two, three, or four appropriate alternatives. To further control for physician preferences, alternatives were randomly selected from a longer list of appropriate alternatives for each participant. Scenarios were about half a page in length, presented online in written format and no time limit was imposed. The clinical scenarios were co-designed during protocol development with the investigator team that included primary care physicians, behavioural economists, and investigators with expertise in research methods. Guidance on designing experimental vignette studies to identify drivers of healthcare variation was followed (Sheringham, 2021).

Scenario 1 featured a patient with chronic hip pain and osteoarthritis and replicated the Redelmeier and Shafir (1995) study, with updates to ensure clinical relevance in 2024 (eg drug names, patient’s profession). In this scenario the patient had been seeing a physiotherapist and walked daily. They had tried one NSAID but stopped due to limited efficacy. The existing management plan (or status-quo option) in this scenario was to refer the patient to an orthopaedic surgeon, without trying a new NSAID. The alternative options presented were to continue with the referral but to also start the patient on an NSAID. Control physicians were presented with one NSAID alternatives and intervention physicians were presented with two NSAID alternatives.

Scenario 2 featured a patient with chronic low-back pain. In this scenario the patient had been managing their back pain with physiotherapy and regular exercise over the last few months. Approximately 2 weeks ago the patient received a 3-day supply of an opioid analgesic (oxycodone) to help manage a flare up. In this scenario the patient had requested another 3-day supply of oxycodone but when the physician initiated the order an alert was triggered, suggesting that they consider an NSAID medicine instead. The status-quo option was to continue with the opioid analgesic and the alternative was to try an NSAID. Control physicians were presented with one NSAID alternative and intervention physicians were presented with two, three or four NSAID alternatives.

Physicians were randomized (1:1) to control or intervention conditions using computerized randomization via the Qualtrics research platform. Physicians in the intervention groups were further randomized (1:1:1) to receive two, three or four alternatives for scenario 2. To ensure data integrity, the independent data manager removed responses that failed their data quality standards (eg rapid completion time or failed attention checks) before providing the final dataset for analysis.
Intervention code [1] 331842 0
Behaviour
Comparator / control treatment
In the control condition, physicians received the same clinical scenarios with one appropriate treatment alternative randomized from a longer list of alternatives.
Control group
Active

Outcomes
Primary outcome [1] 342601 0
The proportion of primary care physicians that chose an alternative treatment option.
Timepoint [1] 342601 0
Immediately after exposure to the scenario and care options.
Secondary outcome [1] 451498 0
The effect of increasing the number of alternatives to three and four alternatives on care choices.
Timepoint [1] 451498 0
Immediately after exposure to the scenario and care options.

Eligibility
Key inclusion criteria
1. Primary care physicians
2. Currently in clinical practice
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
1. No clinical practice hours e.g. academic physician

Study design
Purpose of the study
Educational / counselling / training
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participant flow and randomization were programmed by investigators with support from a Qualtrics data manager. Investigators were blinded to group allocation and responses until the sampling was complete and the survey closed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Physicians were randomized (1:1) to control or intervention conditions using computerized randomization
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The original study observed an absolute difference of 19% between groups. To detect a 14% difference with 80% power and a two-sided alpha of 0.05, we required 198 physicians per condition completing two scenarios. Our primary analysis used a binary logistic regression interaction model with generalized estimation equations (GEE) to estimate the effect of the intervention on the proportion of clinicians choosing an alternative. Our GEE analysis accounted for within participant clustering (as each physician completed two scenarios) and interaction effects (interaction between the group and the clinical scenario). Effect sizes were presented as odds ratios (OR) with 95% confidence intervals (CI). A two-sided P value <.05 was considered statistically significant. As a secondary exploratory analysis, we estimated unadjusted effects in the total sample and in each scenario using three univariate logistic regression models. We also calculated the number and proportion choosing an alternative in the subgroups presented with two, three or four alternatives. Statistical analyses were conducted using R Version 4.3.2.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
3/05/2024
Date of last participant enrolment
Anticipated
Actual
8/05/2024
Date of last data collection
Anticipated
Actual
8/05/2024
Sample size
Target
396
Accrual to date
Final
402
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 28387 0
Royal Prince Alfred Hospital - Camperdown
Recruitment postcode(s) [1] 44608 0
2050 - Camperdown

Funding & Sponsors
Funding source category [1] 319796 0
University
Name [1] 319796 0
The study was supported by a research grant from the Faculty of Medicine and Health, The University of Sydney (CIA Traeger)
Country [1] 319796 0
Australia
Primary sponsor type
University
Name
The study was sponsored by the University of Sydney, Australia.
Address
Country
Australia
Secondary sponsor category [1] 322312 0
Hospital
Name [1] 322312 0
Royal Prince Alfred Hospital
Address [1] 322312 0
Country [1] 322312 0
Australia
Other collaborator category [1] 283635 0
Individual
Name [1] 283635 0
Adrian Traeger, University of Sydney and Institute for Musculoskeletal Health, Royal Prince Alfred Hospital, Sydney Local Health District
Address [1] 283635 0
Country [1] 283635 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 318355 0
Sydney Local Health District Ethics Review Committee (RPAH Zone)
Ethics committee address [1] 318355 0
Ethics committee country [1] 318355 0
Australia
Date submitted for ethics approval [1] 318355 0
15/03/2024
Approval date [1] 318355 0
15/04/2024
Ethics approval number [1] 318355 0
X24-0060 & 2024/STE01243

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

Contacts
Principal investigator
Name 143918 0
A/Prof Adrian Traeger
Address 143918 0
Institute for Musculoskeletal Health, Level 10N, King George V Building, Royal Prince Alfred Hospital (C39) Missenden Road, Camperdown, NSW, 2050 
Country 143918 0
Australia
Phone 143918 0
+610416122784
Fax 143918 0
Email 143918 0
[email protected]
Contact person for public queries
Name 143919 0
Gemma Altinger
Address 143919 0
Institute for Musculoskeletal Health, Level 10N, King George V Building, Royal Prince Alfred Hospital (C39) Missenden Road, Camperdown, NSW, 2050 
Country 143919 0
Australia
Phone 143919 0
+61 2 93519908
Fax 143919 0
Email 143919 0
[email protected]
Contact person for scientific queries
Name 143920 0
Gemma Altinger
Address 143920 0
Institute for Musculoskeletal Health, Level 10N, King George V Building, Royal Prince Alfred Hospital (C39) Missenden Road, Camperdown, NSW, 2050 
Country 143920 0
Australia
Phone 143920 0
+61 2 93519908
Fax 143920 0
Email 143920 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
Yes
Will there be any conditions when requesting access to individual participant data?
Persons/groups eligible to request access:
• Researchers
Conditions for requesting access:
• Yes, conditions apply:
• Requires approval by an ethics committee
What individual participant data might be shared?
• All de-identified individual participant data
What types of analyses could be done with individual participant data?
• Any type of analysis (i.e. no restrictions on data re-use)
When can requests for individual participant data be made (start and end dates)?
From:
After publication of main results
To:
No end date
Where can requests to access individual participant data be made, or data be obtained directly?
• Email of trial custodian, sponsor or committee: [email protected]

Are there extra considerations when requesting access to individual participant data?
No


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.