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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
The Act-F Trial: Does active follow-up of invitation lead to higher participation in bowel screening by Maori, Pacific and Asians?
Scientific title
A randomised controlled trial of the impact on participation rates in the Waitemata bowel screening pilot of existing active follow-up procedures for Maori, Pacific and Asians who do not initially respond to an invitation for bowel screening
Secondary ID [1] 290361 0
Universal Trial Number (UTN)
UTN: U111111874682
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Colorectal cancer 300651 0
Immunochemical faecal occult blood screening for colorectal cancer 300652 0
Condition category
Condition code
Cancer 300499 300499 0 0
Bowel - Back passage (rectum) or large bowel (colon)
Public Health 300500 300500 0 0
Health service research

Study type
Description of intervention(s) / exposure
The intervention consists of a delay of 8 weeks in commencing the standard Active Follow (AF) pathway invitees to bowel screening who have not returned a test kit within 4 weeks of being sent an invitation letter. The standard AF service consists of the following. Eligible individuals are identified and extracted from the Bowel Screening Pilot register. This data is inserted into an Access (Registered Trademark) database. The database is available to the team of Community coordinators who carry out the AF activities. They use the database to filter the population according to the ethnicity that they serve. The Coordination Centre employs 0.4 FTE of Maori Community Coordinators, 0.4 FTE of Samoan/Other Pacific Coordinators and 0.9 FTE of Asian Coordinators. They phone the individuals and record the outcome of the calls. Key Performance Indicators set by the MOH require a minimum of 3 phone calls to be made within a 4 week period, one of which must be made after regular working hours. If a number appears to be invalid other data sources are searched for current contact details. These include the hospital systems, the Primary Health Organisation age/sex registers, the patient’s GP practice, and contacts the Community Coordinators have with their own communities. In the intervention group this active follow-up activity commences 12 weeks after being sent an invitation letter for bowel screening rather than 4 weeks after as in the control group.
Intervention code [1] 296175 0
Early detection / Screening
Comparator / control treatment
The control group is the standard (not delayed) active follow-up pathway as described above. This commences 4 weeks after being sent an invitation letter among those eligible for active follow-up (Maori, Pacific and Asian ethnicity invitees).
Control group

Primary outcome [1] 299928 0
The primary endpoint of the study is the overall difference in the participation rate of people in the intervention group compared with the control group,
Timepoint [1] 299928 0
For each invitee, the primary outcome will be measured at 8 weeks from the date at which they were randomly assigned to the group (and for the intervention group with delayed AF, it will measured prior to their receiving the AF service).
Secondary outcome [1] 328563 0
Ethnic specific differences in the participation rate.
Timepoint [1] 328563 0
As for the primary endpoint, the secondary endpoint will be measured at 8 weeks from the time of randomisation.
Secondary outcome [2] 328589 0
Differences in participation rate according to whether the active follow-up service was provided by the Bowel Screening Coordination Centre or a contracted provider
Timepoint [2] 328589 0
Measured at 8 weeks following randomisation

Key inclusion criteria
All subjects will be recruited from the universe of population eligible for participation in the Waitemata Bowel Screening Pilot. This is (currently) men and women aged 50-74 who are eligible for publicly funded healthcare resident in the geographical area covered by Waitemata District Health Board. If the invitee has not returned a test kit within 4 weeks of the date of invitation, then s/he is sent a reminder letter. In addition, if that individual is recorded to have a Maori, Pacific or Asian ethnicity, then they are entered in the AF pathway. These are the individuals who are eligible to take part in the study.
Minimum age
50 Years
Maximum age
74 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
None other than those which make the invitees ineligible for the active follow-up pathway. Viz. returning a kit within 4 weeks of being sent and invitation or non-Maori, non-Pacific and non-Asian (prioritised) ethnicity.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation concealment will be ensured by adherence to a strict randomisation protocol. A master randomisation key of 10,000 rows will be provided to the Project Manager to import as an Access (Registered Trademark) database. Three times per week, invitees whose test kits were sent out 28 days or more previously and who have not yet returned a test kit will be extracted from the Bowel Screening Pilot Register into an Access (Registered Trademark) database. An access table will be formed of those eligible for AF (i.e. with a prioritised ethnicity recorded as Maori, Pacific or Asian) and this will be appended into the master randomisation key in alphabetical order of the NHI numbers within that batch. The treatment allocation (intervention or control) corresponding to each individual will be copied into that person’s record, and those assigned to the control group will be allocated today’s date as their start date and will be available immediately for follow-up phone calls.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created in an excel file by its random number generator, with numbers between 0 and 1 rounded down to 0 if less than 0.5 (control group) and up to 1 if above 0.5 (intervention group).
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Sample size calculations have been performed considering the trial either as a test of non-inferiority of the intervention (delayed AF) and alternatively as a test of superiority of the control group (immediate AF). In both cases a difference of 5% in the overall participation rate was the critical limit being tested. To perform these sample size calculations it was first necessary to determine what difference in participation during AF would lead to a 5% difference in overall participation, based on the historical (2015) participation within 30 days and during the first 8 weeks of the Active Follow-up period. Sample size calculations were based on power of 90% and 95% confidence limits. Additional detail is available in the study protocol or upon request.

Analysis will be performed on an intention to treat basis. That is the endpoints will be compared for the two groups as defined from the point of randomisation to intervention or control groups and even participants who are no longer living in the DHB or who are not contactable will be included in the analysis. The initial analysis of data will test for any deviations from balance between the two groups by comparing the distribution of basic demographic variables in each. Differences in participation rates between the two groups will be tested by simple bivariate methods (e.g. the Chi square test) and also by logistic regression analysis to permit statistical control for potential confounding variables (age, sex, ethnicity, provider of active follow-up service, time period etc.).

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 8337 0
New Zealand
State/province [1] 8337 0

Funding & Sponsors
Funding source category [1] 294743 0
Government body
Name [1] 294743 0
Waitemata District Health Board
Address [1] 294743 0
15 Shea Terrace
Auckland 0622
Country [1] 294743 0
New Zealand
Primary sponsor type
Debbie Holdsworth
Planning Funding and Outcomes Unit
Auckland and Waitemata District Health Boards
Level 2
15 Shea Terrace
Auckland 0622
New Zealand
Secondary sponsor category [1] 293592 0
Name [1] 293592 0
Address [1] 293592 0
Country [1] 293592 0

Ethics approval
Ethics application status
Ethics committee name [1] 296160 0
Northern A Health and Disability Ethics Committee
Ethics committee address [1] 296160 0
Ministry of Health
Freyberg Building
20 Aitken Street
PO Box 5013
Ethics committee country [1] 296160 0
New Zealand
Date submitted for ethics approval [1] 296160 0
Approval date [1] 296160 0
Ethics approval number [1] 296160 0

Brief summary
Maori, Pacific and Asian participants in bowel screening who do not submit a test kit within one month of being invited currently enter an active follow-up (AF) process whereby attempts are made to contact them by telephone, ensure that they received the invitation, and offer assistance with completing the screening test. This is a rather costly service and we are uncertain whether this cost can be justified by its impact on participation rates. The proposed trial will test this by randomly allocating eligible individuals to the usual active follow-up protocol or to the same active follow-up but delayed by eight weeks. The trial is designed to test whether AF has a significant impact on participation among the recipients of this service by comparing participation rates between the two groups at 8 weeks from the point that they are allocated to their groups. By eight weeks from initiating AF, approximately 90% of participants who will eventually submit a test kit have already done so. Thus the primary endpoint is the difference in participation between intervention and control groups at eight weeks from the time of allocation. Secondary endpoints will examine whether there are ethnic specific differences in this measure and whether there are differences in this outcome between the service provided directly by the Bowel Screening Coordination Centre and that subcontracted to external providers. There will be approximately 7000 subjects in the trial (3500 in each group).
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 69810 0
Dr Peter Sandiford
Address 69810 0
Health Gain Team
Planning Funding and Outcomes
Auckland and Waitemata District Health Boards
Level 1
15 Shea Terrace
Auckland 0622
Country 69810 0
New Zealand
Phone 69810 0
Fax 69810 0
Email 69810 0
Contact person for public queries
Name 69811 0
Dr Peter Sandiford
Address 69811 0
Health Gain Team
Planning Funding and Outcomes
Auckland and Waitemata District Health Boards
Level 1
15 Shea Terrace
Auckland 0622
Country 69811 0
New Zealand
Phone 69811 0
Fax 69811 0
Email 69811 0
Contact person for scientific queries
Name 69812 0
Dr Peter Sandiford
Address 69812 0
Health Gain Team
Planning Funding and Outcomes
Auckland and Waitemata District Health Boards
Level 1
15 Shea Terrace
Auckland 0622
Country 69812 0
New Zealand
Phone 69812 0
Fax 69812 0
Email 69812 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary