ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12625000798460

Ethics application status

Approved

Date submitted

15/07/2025

Date registered

28/07/2025

Date last updated

28/07/2025

Date data sharing statement initially provided

28/07/2025

Date results provided

28/07/2025

Type of registration

Retrospectively registered

Titles & IDs

Public title

Comparing the effect of offering a supermarket voucher to complete a mailed at-home self-test kit for human papillomavirus (HPV) vs. a test kit with no offer in Auckland Maori and Pacific people who are eligible for cervical screening

Scientific title

A randomised controlled trial comparing the effect of offering an incentive with a test kit vs. a test kit alone on the uptake of mailed at-home human papillomavirus (HPV) self-sampling in Maori and Pacific participants eligible for cervical screening in Auckland

Secondary ID [1]

None

Universal Trial Number (UTN)

U1111-1324-8454

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Cervical screening

Human papillomavirus

Condition category

Condition code

Public Health

Health service research

Infection

Sexually transmitted infections

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

The study intervention was the offer of an incentive to complete a mailed at-home HPV self-test. The incentive was a $50 supermarket voucher.

The offer was made in a letter, which was mailed to eligible participants with an HPV self-test kit.

The test kit contained:
1) a study brochure that explained the importance of cervical screening and the purpose of the study, and instructions on how to self-sample and return it for testing;
2) a swab and pre-labelled collection tube;
3) a pre-labelled laboratory test form;
4) a pre-paid courier bag with which to return the sample for testing.

Although the study was conducted prior to the introduction of HPV self-testing to the national screening programme on 12 September 2023, the swab used in the study (BD Onclarity) is one of the options available in the programme.

The duration of the intervention was approximately four months.

Intervention code [1]

Early detection / Screening

Comparator / control treatment

The control group in this study received a mailed at-home HPV self-test kit with a letter to explain the purpose of the kit and the study. This letter did not include an offer of an incentive. Other than the letter, the test kit contents were identical to that in the intervention group.

Control group

Active

Outcomes

Primary outcome [1]

Return rate of self-tests

Timepoint [1]

Data was censored on 21/10/2024

Secondary outcome [1]

None

Timepoint [1]

None

Eligibility

Key inclusion criteria

1. Maori and Pacific people aged 30-69 years
2. Enrolled with the study Primary Health Organisation (PHO)
3. Meeting the National Cervical Screening Programme (NCSP) Clinical Practice Guidelines as eligible for HPV self-testing (i.e. people with a cervix and due for cervical screening)
4. Provided consent to participate in the study
5. The full schedule of reminder text messages and call attempts were completed and at least 77 days had passed since the last reminder
6. No HPV test result was received prior to 22/04/2024

Minimum age

30 Years

Maximum age

69 Years

Sex

Females

Can healthy volunteers participate?

Yes

Key exclusion criteria

1. Total hysterectomy
2. History of cervical cancer
3. No longer residing in Auckland or enrolled with the study PHO
4. Previous high-grade lesion and no test of cure
5. Symptomatic (e.g. abnormal bleeding or discharge)
6. Never been sexually active
7. Were sent more than one previous self-test kit

Study design

Purpose of the study

Prevention

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Allocation was not concealed

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation)
Stratified for ethnicity

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Parallel

Other design features

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

The estimated sample size needed for each of the intervention and control groups was calculated based on a baseline sample return rate of 35%, a power of 0.80, and a significance level of 0.05. Using the sample return rate on 22/01/2024 of 38% in Maori and 32% in Pacific, with a combined average of 34%, we estimated that we can detect at least a 15% increase in sample return rate (i.e. from 35% to 50%), with 169 participants per intervention group for a total of 338 participants required. With >1,200 potential participants, the study should be adequately powered to detect a difference within ethnicities. These calculations were based on consultation with a statistician.

Descriptive analysis was performed to present numbers and percentages overall and for individual subgroups. Univariable logistic regression was performed to compare the subgroups, and the effect size was presented using odds ratios and their corresponding 95% confidence intervals and p-values. A p-value of <0.05 was considered statistically significant. The analyses were conducted using Excel and Stata 18.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

Actual

22/04/2024

Date of last participant enrolment

Anticipated

Actual

3/09/2024

Date of last data collection

Anticipated

Actual

5/09/2024

Sample size

Target

1226

Accrual to date

Final

1226

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Auckland

Funding & Sponsors

Funding source category [1]

Government body

Name [1]

Health New Zealand | Te Whatu Ora, Waitemata District

Address [1]

Country [1]

New Zealand

Primary sponsor type

Government body

Name

Health New Zealand | Te Whatu Ora, Waitemata District

Address

Country

New Zealand

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Southern Health and Disability Ethics Committee

Ethics committee address [1]

https://ethics.health.govt.nz/about/southern-health-and-disability-ethics-committee/

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

27/02/2024

Approval date [1]

19/03/2024

Ethics approval number [1]

21/STH/141

Summary

Brief summary

Prior to the introduction of HPV primary screening and the option for HPV self-testing in September 2023, we began a broad research programme to investigate the implementation of non-standard strategies to improve uptake of HPV self-testing in three pathways (observational study): 1) in general practice via opportunistic offers, 2) mailed at-home testing via text message invite to people enrolled with the study primary health organisation (PHO), and 3) offering on-site and/or take-home testing at various community settings. The second pathway invited all eligible people enrolled with the study PHO (over 25,000 eligible people); of these, 6,067 consented to receive a test kit, but the proportion of participants who returned their sample was low (around 12%). 

We sought to test the offer of an incentive to increase sample return in the priority groups with the lowest return rates (Maori and Pacific) who had consented as part of the second pathway and received our full schedule of text message and call attempt reminders, but did not return their sample. While there is currently no published evidence for the use of participant incentives towards cervical screening in New Zealand, for wahine Maori and Pacific women, providing an incentive after a healthcare appointment is akin to the cultural concepts of manaakitanga and reciprocity, respectively; small gifts or koha may be considered as an acknowledgement of their decision to be screened. In New Zealand, incentives were a component of smoking cessation programmes during pregnancy and the COVID-19 vaccination programme.

The objective of this nested randomised controlled study was to investigate the effect of offering an incentive upon sample return compared with no offer of an incentive alongside a repeat mailed test kit on the sample return rate in eligible Maori and Pacific who had previously consented, but who had not returned their sample. The control group of Maori and Pacific were mailed a test kit but were not an incentive.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Karen Bartholomew

Address

Health Gain Development; Planning, Funding and Outcomes; Health New Zealand | Te Whatu Ora; Q4, level 2, Smales Farm; 74 Taharoto Rd; Takapuna; Auckland 0622

Country

New Zealand

Phone

+64212115629

Fax

[email protected]

Contact person for public queries

Name

Karen Bartholomew

Address

Health Gain Development; Planning, Funding and Outcomes; Health New Zealand | Te Whatu Ora; Q4, level 2, Smales Farm; 74 Taharoto Rd; Takapuna; Auckland 0622

Country

New Zealand

Phone

+64212115629

Fax

[email protected]

Contact person for scientific queries

Name

Karen Bartholomew

Address

Health Gain Development; Planning, Funding and Outcomes; Health New Zealand | Te Whatu Ora; Q4, level 2, Smales Farm; 74 Taharoto Rd; Takapuna; Auckland 0622

Country

New Zealand

Phone

+64212115629

Fax

[email protected]

Data sharing statement

Will the study consider sharing individual participant data?

No
No IPD sharing reason/comment: The data used and analysed in the study contain identifiable individual patient information, including that of Maori. The data are not publicly available due to the data confidentiality and privacy restrictions and Maori data sovereignty considerations, but are available from the corresponding author on reasonable request and corresponding approvals.

What supporting documents are/will be available?

Type	Other Details	Attachment
Ethical approval		HDEC letter _ incentivisation amendment approval.pdf
Informed consent form		E-consent webpage.pdf
Other	Participant information sheet	PIS.pdf

Results publications and other study-related documents

Documents added manually

Type	Is Peer Reviewed?	DOI	Citations or Other Details	Attachment
Plain language summary	No			Plain language summary.pdf

Documents added automatically

No additional documents have been identified.

Trial Review

Documents added manually

Documents added automatically