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Trial registered on ANZCTR

Registration number

ACTRN12615001158550

Ethics application status

Approved

Date submitted

17/02/2015

Date registered

30/10/2015

Date last updated

30/07/2018

Type of registration

Retrospectively registered

Titles & IDs

Public title

Supporting expectant mothers to quit smoking

Scientific title

Promoting smoking cessation in pregnant smokers: Quit contingent participant and partner vouchers to motivate long term cessation.

Secondary ID [1]

Nil

Universal Trial Number (UTN)

Trial acronym

SEMQ

Linked study record

Health condition

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

Tobacco smoking in pregnancy

Condition category

Condition code

Reproductive Health and Childbirth

Normal pregnancy

Mental Health

Addiction

Reproductive Health and Childbirth

Antenatal care

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Study participants will be allocated to one of two groups (Control Group [CG] or Treatment Group [TG]) during the baseline/enrolment visit. In the Control group/condition, only the participant (pregnant smoker) will be eligible to receive the voucher incentives. In the Treatment group/condition, the participant will be asked to nominate a quit partner (where appropriate their spouse) who will also be eligible to receive incentive vouchers if the participant verifies as quit during monthly follow-up.

Control group participants will be advised that they will be eligible to receive a monthly incentive ($50 voucher) if, during follow up study visits and telephone calls, they self-report and verify (via exhaled breath carbon monoxide [CO] measurement of between 0-6ppm) as quit. Participants will be required to attend three study visits (Baseline/Enrolment [V1], end of pregnancy [V2], and two months postpartum [V3]) where they will complete questionnaires relating to their smoking history, intention to quit, smoking knowledge, reasons for quitting, and perceived partner support. Additionally, researchers will contact participants monthly during the study, via telephone, to determine their smoking status. If during these monthly telephone calls the participant reports being quit, they will be invited back to the study centre to verify their quit status, and receive the quit contingent incentive. Study duration will be approximately 12 months, from time of enrolment antepartum to 6 months postpartum. A final 12 month postpartum follow up telephone call will also be conducted to determine the long-term effects of the intervention. All participants will be eligible to receive up to $570 if they verify as abstinent for the duration of the study. The $570 comprises up to 11 x $50 vouchers if they have quit, and 2 x $10 vouchers for visits V1 and V3.

In the Treatment condition, the participant and their support partner will be eligible to receive up to $570 and $550 respectively, if the pregnant participant verifies as quit during monthly study visits for the duration of the study. Note: the total incentive voucher sum is less for the partner given they do not attend the V1 and V3 visits, and therefore do not receive the $10 vouchers allocated to these visits.

All study participants will additionally be provided with quit materials and a ‘Partner Pack’, which will provide their ‘quit buddy’ with useful resources. The participant quit materials comprise publicly available pregnancy-specific written materials (developed by the Australian Government Dept of Health and Cancer Council Australia) and provided by Quit Tasmania (for example, "Quit for you, Quit for two", "Smoking and pregnancy factsheet", "Health risks of smoking during pregnancy", "Sudden Infant Death Syndrome: SIDS and Kids information sheet on smoking", "Quit Book" and Quitline information), as well as a list of other publicly available government-funded resources (smartphone apps, websites) and health professionals (GP, smoking cessation clinical nurse consultant) who can assist in the quit process. The 'Partner Pack' comprises publicly available written materials (provided by Cancer Council and Quitline) largely directed at the male partners (irrespective of smoking status) of expectant women who smoke, and provides information on how best to support the expectant woman in her quit attempt (e.g. "The effect of second-hand smoke on children", "12 tips to support your quitter", "Helping a smoker quit: Do's and don'ts", "Important news for fathers who smoke", "Products to help you quit smoking", and "Quit for good factsheet").

Intervention code [1]

Treatment: Other

Intervention code [2]

Behaviour

Comparator / control treatment

Control group participants will be informed that they will be eligible to receive a monthly incentive ($50 voucher) if, during follow up study visits and telephone calls, they self-report and verify (using CO monitor, value of between 0-6ppm) as quit. Participants will be required to attend three study visits (Baseline/Enrolment [V1], end of pregnancy [V2], and two months postpartum [V3]) where they will complete questionnaires relating to their smoking history, intention to quit, and perceived partner support. Additionally, researchers will contact participants monthly during the study (over approximately a 12 month period, from study enrolment antepartum – 6 months postpartum) via telephone to determine smoking status. If during these monthly telephone calls the participant reports being quit, they will be invited back to the study centre to verify their smoking status and receive the quit contingent incentive. A final 12 month postpartum follow up telephone call will also be conducted to determine the long-term effects of the intervention. All participants will be eligible to receive up to $570 if they verify as abstinent for the duration of the study (see details in intervention description). All participants will be provided with quit materials and a ‘Partner Pack’ which will provide their ‘quit buddy’ with useful resources for supporting the participant's quit attempt.

Data from the 'historical' control group will be obtained from the Tasmanian Council of Obstetric and Paediatric Morbidity and Mortality (COPMM) data sets, published in a yearly report by the Tasmanian Dept of Health and Human Services. Data relating to a range of perinatal clinical indices, including drug and alcohol use, is routinely collected from all pregnant women in Tasmania. The historical data on smoking prevalence intra- and post-partum, collected between May 2013 and Oct 2014 (a 17 month time period as per the SEMQ study), will enable a comparison to be made of the efficacy of the study intervention (financial incentives) in enhancing smoking cessation rates during pregnancy when compared to the prevalence rates seen in response to "usual care" smoking cessation interventions used historically in the Tasmanian public hospital antenatal setting.

Control group

Active

Outcomes

Primary outcome [1]

The percentage of women receiving antenatal care (statewide), who quit smoking during pregnancy (first 20 weeks vs second 20 weeks) in the study timeframe (2015-2016, see below), will be compared to the percentage in previous years (based on historical data e.g., 2012, 2011, 2010 antenatal data provided by DHHS).
Note: recruitment commenced in May 2015 in the North and North West of Tasmania, and in Sept 2015 at the Royal Hobart Hospital and services in the south of the state. Recruitment will conclude in Sept 2016.

This outcome (smoking cessation) will be assessed by biochemical verification of the expectant woman's self-reported smoking status, via exhaled breath Carbon Monoxide (CO) measurement. A threshold value of 7ppm will discriminate smoking status, with 0-6ppm indicating non-smoking status and greater than or equal to 7ppm indicating current smoking.

Timepoint [1]

17 months following start of study recruitment.

Primary outcome [2]

Primary outcome 2 (the effect of incentivised partner support in facilitating maternal smoking cessation) will be measured by comparing the proportion/percentage of women verified (via CO monitor and self-report) as quit at end of pregnancy (~8 months gestation) and postpartum (2 and 12 months postpartum) in the control (pregnant smoker incentivised) compared to treatment group (both pregnant woman and partner incentivised).

Timepoint [2]

This outcome will be measured at: (i) end of pregnancy (~8 months gestation; V2), (ii) two months postpartum (V3), and (iii) 12 months postpartum. These time points will occur at approximately 5 , 8 and 18 months, respectively, post study enrolment.

Secondary outcome [1]

The quality of partner interaction, and it's influence on maternal smoking cessation (secondary outcome 1), will be evaluated by comparing the Partner Interaction Questionnaire (PIQ) score ratios at three time points (see below) between those women biochemically verified as having quit smoking compared with those self-reporting as not quit.
Note: a high ratio PIQ score indicates that the woman has reported a greater number of positive compared to negative support behaviours from the partner).

Timepoint [1]

This outcome will be measured at 3 time points: (i) end of pregnancy (~8 months gestation; V2), (ii) two months postpartum (V3), and (iii) 12 months postpartum.
These time points will occur at approximately 5 , 8 and 18 months, respectively, post study enrolment.

Eligibility

Key inclusion criteria

Pregnant (> 16 years of age)
Current smoker (using Prenatal Screening Guide)
Attending any statewide public hospital antenatal service (either clinic-based service or outreach midwifery service) for routine antenatal care

Minimum age

16 Years

Maximum age

No limit

Sex

Females

Can healthy volunteers participate?

Key exclusion criteria

Non-smoker (using Prenatal Screening Guide)
Cognitive or intellectual impairment that renders the participant unable to complete the participation requirements (e.g., completion of surveys, attend organised study appointments)

Study design

Purpose of the study

Treatment

Allocation to intervention

Non-randomised trial

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

Participants will be recruited from the antenatal units (i.e., both clinic-based and outreach services) of statewide public hospitals in Tasmania (Launceston General Hospital, Royal Hobart Hospital, North West Regional Hospital). Antenatal staff (O&G physicians, registrars, and midwives) will provide study information (in the form of a flyer) to eligible participants during antenatal appointments (i.e., to pregnant women who answer ‘yes’ to the routine question of ‘whether the mother smoked a cigarette at any time during the first 20 weeks of the pregnancy’). Potential participants will then contact the researcher (phone or email) if they are interested in participating. Researchers will screen potential participants to determine eligibility using a set protocol, which is based on a published, best-practice protocol (Melvin & Tucker, 2000). This screening process will involve a more detailed assessment of smoking status and participant eligibility.

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

Participants recruited in the first three months (location dependent, e.g. LGH: May, June, July 2015; RHH: Sept, Oct, Nov 2015) will be allocated to the control group (CG). Participants recruited in the following three months will be allocated to the treatment group (TG). Recruitment for the next 14 months will follow the same pattern. An ABAB design is more appropriate than a fully randomised, parallel group controlled trial since there is great potential for the women recruited, due to the small sample pool, to know each other or discuss their participation in the study during routine antenatal classes and appointments (particularly in the case of the smaller regional hospitals, e.g., LGH, Mersey Hospital). Which phase of the ABAB design participants are being recruited to will be known only by the research team. This way, potential bias in the way antenatal care is delivered to the two research groups will be avoided.

Masking / blinding

Blinded (masking used)

Who is / are masked / blinded?

The people receiving the treatment/s

Intervention assignment

Other

Other design features

The ABAB parallel design was specifically chosen to help optimise participant blinding. Given the relatively small population of Tasmania, and particularly the regional centres and small regional hospitals from which study participants will be recruited, there is a high likelihood that participants will know or encounter other individuals enrolled in the study.

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

To determine if incentivised partner support (and incentives in general) are more effective than usual care, the percentage of women who quit during antenatal care (indicated by smoking in first 20 weeks of pregnancy, but having quit in the second 20 weeks of pregnancy) in 2015 (for 12 months of the study intervention) will be compared with historical cohort data (including 2012, as well as 2011-2005; data provided by DHHS). Using sample sizes of 200 (2015) and 260 (2011 – greater numbers expected in previous cohorts), there would be power of 0.88 to detect a small to medium effect size of 0.3. However we anticipate a larger effect size (see Donatelle et al., 2000 reference below), especially since less than 1% quit during pregnancy under usual care treatment in 2011 (DHHS, 2012).

To determine if incentivised partner support is more effective than incentives only, Treatment and Control Group abstinence rates at end of pregnancy (~8 months gestation, V2), 2-months postpartum (V3) and 12 months postpartum will be compared using the chi-square test. Whilst no study to our knowledge has compared participant incentive with participant plus partner incentive, Donatelle et al. (2000) compared a usual care control group with an incentive plus partner incentive treatment group and found that at the end of pregnancy, 32% of treatment group participants (n=105) had quit compared with 9% in the control group (n=102), with a large effect size found (chi-square = 18.4, n=207, d=0.62). Since the control group in the present study will also be receiving incentives, it is anticipated that the effect size will be moderate, rather than large. As such, to determine if there is a significant difference between treatment and control quit rates at the end of pregnancy (and postpartum), with the power of .80 to detect an effect size of .30, the study will require a total sample size of 108. Since it is anticipated that data will be obtained from 200 women, even with attrition, this sample size should be sufficient to detect the anticipated effect size.

To determine if quality of support determines abstinence, participants, regardless of group allocation (Treatment vs Control) will be regrouped to either PIQ-POS or PIQ-NEG, as determined by the ratio of positive compared to negative support they report receiving from their partners. The PIQ-POS and PIQ-NEG smoking abstinence rates (%) at the three time points (end of pregnancy, 2 months postpartum, and 12 month postpartum) will be compared. To our knowledge, this is the only study to compare partner support (PIQ20) received from incentivised and non-incentivised partners, and thus it is not known exactly what effect size to expect. Furthermore, to our knowledge, only underpowered pilot studies have compared social support with a control. Cohen and Lichtenstein’s (1990) study found female quitters (ratio = 4.08, n=155) reported receiving significantly more partner support compared to male quitters (ratio = 2.60, n=66), t(167) = 2.03, p <.04, d = 0.31, r = 0.16. If this is used as a guide, independent samples t-test to compare the ratio of positive to negative partner support behaviours received by women in the Treatment versus Control group, with power of .80, to detect an effect size of .30, would require a sample of n= 278 (139/139) + 10% ~306. Since the present study will provide a voucher incentive to treatment group partners to be effective quit buddies, we expect a larger effect size. As such, to detect a medium to large effect of.40, we would require a total sample size of n=156 (78/78). By over recruiting 10% to account for attrition, we would require a sample size of ~n = 172.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

Actual

23/06/2015

Date of last participant enrolment

Anticipated

30/09/2016

Actual

30/12/2016

Date of last data collection

Anticipated

29/12/2017

Actual

29/12/2017

Sample size

Target

180

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

TAS

Recruitment hospital [1]

Launceston General Hospital - Launceston

Recruitment hospital [2]

Royal Hobart Hospital - Hobart

Recruitment hospital [3]

Mersey Community Hospital - Latrobe

Recruitment hospital [4]

North West Regional Hospital - Burnie

Recruitment postcode(s) [1]

7250 - Launceston

Recruitment postcode(s) [2]

7000 - Hobart

Recruitment postcode(s) [3]

7307 - Latrobe

Recruitment postcode(s) [4]

7320 - Burnie

Funding & Sponsors

Funding source category [1]

Charities/Societies/Foundations

Name [1]

Cancer Council Tasmania

Address [1]

180 – 184 Collins Street
Hobart, Tasmania, 7000

Country [1]

Australia

Funding source category [2]

University

Name [2]

University of Tasmania, Faculty of Health Fellowship

Address [2]

School of Health Sciences
University of Tasmania
Locked Bag 1322
Launceston, Tasmania, 7250

Country [2]

Australia

Primary sponsor type

Individual

Name

Dr Mai Frandsen

Address

School of Health Sciences
University of Tasmania
Locked Bag 1322
Launceston, Tasmania, 7250

Country

Australia

Secondary sponsor category [1]

Individual

Name [1]

Dr Stuart Ferguson

Address [1]

School of Pharmacy
Private Bag 26
University of Tasmania
Hobart, Tasmania, 7001

Country [1]

Australia

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Human Research Ethics Committee (Tasmania) Network

Ethics committee address [1]

Office of Research Services
University of Tasmania
Private Bag 1
Hobart Tasmania 7001

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

10/11/2014

Approval date [1]

11/02/2015

Ethics approval number [1]

H0014568

Summary

Brief summary

The purpose of this pilot study is to determine whether providing quit incentives ('paying' [with vouchers'] for abstinence) to pregnant smokers will motivate them to quit during their pregnancy and stay quit once the baby is born. The study will determine if such an incentives intervention is more effective than the current 'usual care' smoking cessation protocols used in public hospital antenatal clinics in Tasmania. Furthermore, the proposed research will determine if incentivising partner support, that is, paying the partner of the pregnant smoker to be a more effective and active 'quit buddy', is more effective than providing cessation-contingent incentives to the expectant mother alone. All participants, during the initial study enrolment visit, will receive publicly available self-help quit materials developed especially for pregnant smokers, as well as a ‘partner pack’ containing materials especially designed for supporters of people trying to quit. At the completion of the initial enrolment visit, participants will be allocated to one of two groups: Control group (CG) or Treatment group (TG). For participants allocated to the Control group, only the participant (pregnant smoker) will be eligible to receive a monthly $50 voucher incentive if they verify (via exhaled breath carbon monoxide [CO] sample < 7ppm) as quit; for participants allocated to the Treatment group, both participant and nominated support person (where possible, spouse) will each be eligible to receive a monthly $50 voucher incentive if the participant verifies (CO sample < 7ppm) as being quit. After the initial enrolment visit
(V1), where baseline measures, quit materials, and group allocation takes place, the researcher will telephone the participants on a monthly basis to determine smoking status. If during these calls the participant self-reports as quit, they will be invited to attend the study centre where, upon verification (via CO monitor) of their quit status, they will receive the $50 voucher incentive (plus partner incentive if in the TG). As well as participating in monthly telephone calls until 6 months postpartum (approximately 10 telephone calls), participants, regardless of smoking status, will be required to attend study visits at the end of pregnancy (V2; approximately 8 months gestation) and at 2 months postpartum (V3). During these study visits, participants will be asked to complete follow-up questionnaires (e.g., intention to quit, reasons for quitting, partner interaction questionnaire, smoking knowledge quiz) and have their smoking status verified (via CO monitor). If the participant quits smoking after the initial enrolment visit they may be eligible for a total incentive amount of $570 (plus a further $550 for TG partners). Participants will also participate in a final 12-month follow-up telephone call to determine long term quit status.

Trial website

Trial related presentations / publications

Public notes