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Trial registered on ANZCTR


Registration number
ACTRN12619001503112
Ethics application status
Approved
Date submitted
28/10/2019
Date registered
31/10/2019
Date last updated
28/11/2019
Date data sharing statement initially provided
31/10/2019
Date results information initially provided
28/11/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Reducing musculoskeletal diagnostic imaging requests in general practice
Scientific title
Reducing musculoskeletal diagnostic imaging by high requesting Australian general practitioners using feedback: a cluster randomised controlled trial using a factorial design
Secondary ID [1] 299647 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
low back conditions 314974 0
neck conditions 315010 0
shoulder conditions 315011 0
hip conditions 315012 0
knee conditions 315013 0
ankle/hind foot conditions 315014 0
Condition category
Condition code
Musculoskeletal 313314 313314 0 0
Osteoarthritis
Musculoskeletal 313359 313359 0 0
Other muscular and skeletal disorders
Public Health 313360 313360 0 0
Health service research

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Brief name: Feedback on musculoskeletal diagnostic imaging requests

All General Practitioners (GPs) allocated to an intervention group will receive feedback on their diagnostic imaging request rate for 11 musculoskeletal imaging services compared with the request rate of their GP peers. The targeted imaging services are: 1) Low back CT, 2) Low back x-ray, 3) Neck CT, 4) Neck x-ray, 5) Neck MRI, 6) Shoulder x-ray, 7) Shoulder ultrasound, 8) Hip x-ray, 9) Hip ultrasound, 10) Knee x-ray, 11) Ankle/hind foot ultrasound.

GPs will be allocated to a control group (Group 1) or one of four intervention groups with feedback as follows:

• Group 2: Feedback delivered by mail on one occasion (at month 0) that illustrates (i) in graphical format, the GP’s overall diagnostic imaging request rate per 1000 consultations compared with his/her GP peers over the previous calendar year (January to December 2018), and (ii) in tabular format, the GP’s request rate per 1000 consultations for each musculoskeletal imaging service compared with his/her GP peers over the previous calendar year.
• Group 3: Feedback as described in Group 2, but supplemented with highlighted text in the table designed to draw the GP’s attention to those musculoskeletal imaging services where they are in the top 20% of requesters.
• Group 4: Feedback as described in Group 2, but supplemented with feedback on a second occasion (at month 9-12) illustrating (i) in graphical format the GPs’ overall diagnostic imaging request rate per 1000 consultations compared with his/her GP peers over the six month period following the first letter and previous calendar year; and (ii) in tabular format, the GP’s request rate per 1000 consultations for each musculoskeletal imaging service compared with his/her GP peers over the six month period following the first letter.
• Group 5: Feedback as described in Groups 3 and 4.

Purpose of the intervention(s): To reduce musculoskeletal diagnostic imaging requests by high-requesting GPs
Procedures: Feedback letter to high-requesting GPs
Materials: Feedback letter
Provider: Australian Government Department of Health
Mode of delivery: Mailed to participants at their nominated mailing address
Tailoring: Feedback on musculoskeletal diagnostic imaging request rate individualised to the recipient
Fidelity: Return to sender documented
Intervention code [1] 315903 0
Behaviour
Comparator / control treatment
Current practice (no intervention). GPs in the control group (Group 1) will receive no feedback information on their musculoskeletal diagnostic imaging requesting behaviour during the trial
Control group
Active

Outcomes
Primary outcome [1] 321791 0
Rate of diagnostic imaging requests for each GP per 1000 Category 1 services for the targeted 11 musculoskeletal imaging services that are rendered by a radiologist over the 12 months following randomisation using Medicare Benefits Schedule (MBS) data. Targeted diagnostic imaging (DI) services are: 1) Low back CT, 2) Low back x-ray, 3) Neck CT, 4) Neck x-ray, 5) Neck MRI, 6) Shoulder x-ray, 7) Shoulder ultrasound, 8) Hip x-ray, 9) Hip ultrasound, 10) Knee x-ray, 11) Ankle/hind foot ultrasound
Timepoint [1] 321791 0
12 months after randomisation
Secondary outcome [1] 376211 0
Rate of diagnostic imaging requests for each GP per 1000 Category 1 services for the targeted 11 musculoskeletal imaging services that are rendered by a radiologist using MBS data
Timepoint [1] 376211 0
Baseline, and at 6 and 18 months after randomisation
Secondary outcome [2] 376212 0
Rate of low back CT requests for each GP per 1000 Category 1 services using MBS data
Timepoint [2] 376212 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [3] 376213 0
Rate of low back x-ray requests for each GP per 1000 Category 1 services using MBS data
Timepoint [3] 376213 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [4] 376214 0
Rate of neck CT requests for each GP per 1000 Category 1 services using MBS data
Timepoint [4] 376214 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [5] 376215 0
Rate of neck x-ray requests for each GP per 1000 Category 1 services using MBS data
Timepoint [5] 376215 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [6] 376216 0
Rate of neck MRI requests for each GP per 1000 Category 1 services using MBS data
Timepoint [6] 376216 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [7] 376217 0
Rate of shoulder x-ray requests for each GP per 1000 Category 1 services using MBS data
Timepoint [7] 376217 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [8] 376218 0
Rate of shoulder ultrasound requests for each GP per 1000 Category 1 services using MBS data
Timepoint [8] 376218 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [9] 376219 0
Rate of hip x-ray requests for each GP per 1000 Category 1 services using MBS data
Timepoint [9] 376219 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [10] 376220 0
Rate of hip ultrasound requests for each GP per 1000 Category 1 services using MBS data
Timepoint [10] 376220 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [11] 376221 0
Rate of knee x-ray requests for each GP per 1000 Category 1 services using MBS data
Timepoint [11] 376221 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [12] 376222 0
Rate of ankle/hind foot ultrasound requests for each GP per 1000 Category 1 services using MBS data
Timepoint [12] 376222 0
Baseline, and at 6, 12 and 18 months after randomisation
Secondary outcome [13] 376223 0
Rate of ankle x-ray requests for each GP per 1000 Category 1 services using MBS data
Timepoint [13] 376223 0
Baseline, and at 6, 12 and 18 months after randomisation

Eligibility
Key inclusion criteria
General practitioners (GPs) practising in Australia, who are in the top 20% of GP requesters for 11 targeted musculoskeletal diagnostic imaging services and in the top 20% of requesters for at least 4 individual items. Targeted diagnostic imaging are: 1) Low back CT, 2) Low back x-ray, 3) Neck CT, 4) Neck x-ray, 5) Neck MRI, 6) Shoulder x-ray, 7) Shoulder ultrasound, 8) Hip x-ray, 9) Hip ultrasound, 10) Knee x-ray, 11) Ankle/hind foot ultrasound. Only diagnostic imaging requests that lead to a service being rendered by a radiologist and for which a Medicare Benefits Schedule (MBS) claim is made are in scope.
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
1. GPs with <1000 Category 1 services .
2. GPs who did not make any in-scope diagnostic imaging requests within the nominated 12-month period (1 January 2018 to 31 December 2018).
3. GPs who participated in user testing of the intervention
4. GPs who are currently or have been involved in a Department of Health compliance activity within the past 12 months.

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)
Randomisation will be conducted using a replicable randomisation algorithm in the statistical program R. Allocation will occur on a single occasion.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation sequence will be generated using a computer-generated randomisation algorithm in the statistical program R. GPs will be clustered based on exact-matched primary practice addresses. Randomisation of GPs will be stratified by geographic region (urban, regional/rural-remote: MMM1, MMM2-7).
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



The people analysing the results/data
Intervention assignment
Factorial
Other design features
GPs are randomly allocated to receive either no feedback intervention (control) or feedback. Within those allocated to feedback, GPs are first randomly allocated to feedback on one or two occasions (Factor 1) and then standard or enhanced feedback display (Factor 2).
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Power calculation:
We expect to randomise a total of 3,820 general practitioners from 2,271 general practices. 1,444 practices will comprise one provider only with the remainder including between 2 and 12 providers. To be conservative, the sample size calculation assumes 2,271 clusters of size one.

The primary endpoint will be the rate of diagnostic imaging requests for each GP per 1000 Category 1 services. A sample size of 2,271 general practices will be randomised 4:1 between the intervention and control arms. This will provide >90% power to detect a difference as small as 1.2 requests in the average rate of diagnostic imaging requests. This calculation assumes a standard deviation of 7 and a two-sided type-I error rate of 5%.

This sample size will also provide >90% power to detect a difference of 1.2 requests in the average rate of diagnostic imaging requests between general practices receiving feedback on one occasion (n=908) vs. two occasions (n=908) and between those receiving feedback without (n=908) vs with (n=908) highlighted text. For both of these secondary comparisons, the type-I error rate is set at 2.5% 2-sided to control for multiplicity.

Statistical analysis:
The main analysis will consist of comparing the rate of diagnostic imaging requests for each GP per 1000 Category 1 services. Data will be aggregated at the GP level and analysed using linear regression adjusted for the baseline imaging rate of each GP as well as the variables used to stratify the randomisation. Clustering of GPs by practice will be accounted for by using a random effect model or generalised estimating equations.

The primary comparison will consist of comparing the four intervention arms to the control arm. The overall effect of the intervention will be estimated as the adjusted mean difference together with its 95% confidence interval. Using the same linear regression model, we will also estimate the effect of the number of feedback occasions (one vs two) and the effect of the highlighted text (no vs yes) using adjusted mean differences and 97.5% confidence intervals. A similar approach will be used to analyse the secondary outcomes.

Additional models with additional baseline covariates will be considered together with subgroup analyses. Details will be pre-specified in a separate statistical analysis plan developed with no access to unblinded trial data.

Recruitment
Recruitment status
Active, not recruiting
Date of first participant enrolment
Anticipated
Actual
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)
ACT,NSW,NT,QLD,SA,TAS,WA,VIC

Funding & Sponsors
Funding source category [1] 304119 0
Government body
Name [1] 304119 0
Australian Government Department of Health
Address [1] 304119 0
PO Box 9848, Canberra ACT 2601
Country [1] 304119 0
Australia
Primary sponsor type
Government body
Name
Australian Government Department of Health
Address
PO Box 9848, Canberra ACT 2601
Country
Australia
Secondary sponsor category [1] 304335 0
None
Name [1] 304335 0
Address [1] 304335 0
Country [1] 304335 0
Other collaborator category [1] 280999 0
Other Collaborative groups
Name [1] 280999 0
Wiser Healthcare Collaboration
Address [1] 280999 0
c/o Paul Glasziou, Bond University, 14 University Drive, Robina QLD 4226
Country [1] 280999 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 304606 0
Bond University Human Research Ethics Committee
Ethics committee address [1] 304606 0
Bond University
University Drive
Robina, QLD, 4229
Ethics committee country [1] 304606 0
Australia
Date submitted for ethics approval [1] 304606 0
12/07/2019
Approval date [1] 304606 0
27/08/2019
Ethics approval number [1] 304606 0
LA03323

Summary
Brief summary
The aim of this study is to evaluate the effectiveness of feedback for reducing musculoskeletal diagnostic imaging requests in general practice compared with control. A secondary aim is to evaluate which forms of feedback are most effective in reducing musculoskeletal diagnostic imaging requests.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 97558 0
Dr Belinda Swan
Address 97558 0
Australian Government Department of Health
PO Box 9848, Canberra ACT 2601
Country 97558 0
Australia
Phone 97558 0
+61 02 6289 5631
Fax 97558 0
Email 97558 0
diagnostic.imaging@health.gov.au
Contact person for public queries
Name 97559 0
Dr Belinda Swan
Address 97559 0
Australian Government Department of Health
PO Box 9848, Canberra ACT 2601
Country 97559 0
Australia
Phone 97559 0
+61 02 6289 5631
Fax 97559 0
Email 97559 0
diagnostic.imaging@health.gov.au
Contact person for scientific queries
Name 97560 0
Dr Denise O’Connor
Address 97560 0
Monash Department of Clinical Epidemiology, Cabrini Institute, and Department of Clinical Epidemiology and Preventive Medicine, Monash University
4 Drysdale Street, Malvern VIC 3144
Country 97560 0
Australia
Phone 97560 0
+61 03 9508 3499
Fax 97560 0
Email 97560 0
denise.oconnor@monash.edu

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
No
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary