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Hypertension is the leading modifiable risk factor for cardiovascular disease and mortality. Adopting lifestyle modifications, like increasing physical activity (PA), can be an effective strategy in blood pressure (BP) control, but many adults do not meet the PA guidelines. Financial incentive interventions have the power to increase PA levels but are often limited due to cost. Further, mobile health technologies can make these programs more scalable. There is a gap in the literature about the most feasible and effective financial incentive PA framework; thus, pay-per-minute (PPM) and self-funded investment incentive (SFII) frameworks were explored.
The aims were to (1) determine the feasibility (recruitment, engagement, and acceptability) of an 8-week mobile-based PPM and SFII hypertension prevention PA program and (2) explore the effects of PPM and SFII interventions relative to a control on the PA levels, BP, and PA motivation.
In total, 55 adults aged 40-65 years not meeting the Canadian PA guidelines were recruited from Facebook and randomized into the following groups: financial incentive groups, PPM or SFII, receiving up to CAD $20 each (at the time of writing: CAD $1=US $0.74), or a control group without financial incentive. PPM participants received CAD $0.02 for each minute of moderate-to-vigorous PA (MVPA) per week up to the PA guidelines and the SFII received CAD $2.50 for each week they met the PA guidelines. Feasibility outcome measures (recruitment, engagement, and acceptability) were assessed. Secondary outcomes included changes in PA outcomes (MVPA and daily steps) relative to baseline were compared among PPM, SFII, and control groups at 4 and 8 weeks using linear regressions. Changes in BP and relative autonomy index relative to baseline were compared among the groups at follow-up.
Participants were randomized to the PPM (n=19), SFII (n=18), or control (n=18) groups. The recruitment, retention rate, and engagement were 77%, 75%, and 65%, respectively. The intervention received overall positive feedback, with 90% of comments praising the intervention structure, financial incentive, and educational materials. Relative to the control at 4 weeks, the PPM and SFII arms increased their MVPA with medium effect (PPM vs control: η2p=0.06, mean 117.8, SD 514 minutes; SFII vs control: η2p=0.08, mean 145.3, SD 616 minutes). At 8 weeks, PPM maintained a small effect in MVPA relative to the control (η2p=0.01, mean 22.8, SD 249 minutes) and SFII displayed a medium effect size (η2p=0.07, mean 113.8, SD 256 minutes). Small effects were observed for PPM and SFII relative to the control for systolic blood pressure (SBP) and diastolic blood pressure (DBP) (PPM: η2p=0.12, Δmean SBP 7.1, SD 23.61 mm Hg; η2p=0.04, Δmean DBP 3.5, SD 6.2 mm Hg; SFII: η2p=0.01, Δmean SBP −0.4, SD 1.4 mm Hg; η2p=0.02, Δmean DBP −2.3, SD 7.7 mm Hg) and relative autonomy index (PPM: η2p=0.01; SFII: η2p=0.03).
The feasibility metrics and preliminary findings suggest that a future full-scale randomized controlled trial examining the efficacy of PPM and SFII relative to a control is feasible, and studies with longer duration are warranted.
Hypertension and prehypertension are leading risk factors for strokes, ischemic heart disease, and other vascular diseases, and currently lead to 8.5 million deaths globally [
A recent systematic review reported that both gain and loss-framed financial incentives can promote PA outcomes (leisure-time PA, walking behavior, PA guidelines, kilocalories expended, and total PA) with small-to-moderate effect [
An innovative and sustainable solution could be a self-funded investment incentive (SFII). This funding model is similar to a social impact bond, a contract between a governing authority and the public sector to produce better social outcomes, that is, better health [
The primary objective of this study was to determine the feasibility (recruitment, engagement, and acceptability) of an 8-week mobile-based PPM and SFII hypertension prevention program. The secondary objectives of this study were to explore the effects of PPM and SFII interventions relative to a control on PA levels, BP, and PA motivation following the intervention.
Based on previous literature, it was hypothesized that >70% of interested individuals would be recruited [
This randomized feasibility pilot study aligns with the goals of phase IIb of the ORBIT model to determine the feasibility of conducting a trial of a full intervention [
All participants provided consent before the start of the study. Ethics approval for this study was obtained through the Human Research Ethics Board at the University of Victoria (protocol 20-0016). All participants provided written informed consent and were informed that their details would be deidentifiable through a unique participant ID and anonymous email address for accessing study content. Independent of the study group, all participants received CAD $20.
Adults living in British Columbia, Canada, were recruited through Facebook. To be eligible for this study, participants needed to be (1) 40-65 years old, (2) not meeting the Canadian PA guidelines of 150 minutes of MVPA per week (assessed by the Get Active Questionnaire [
Participants were introduced to an 8-week Healthy Hearts education program, with 1 lesson during the baseline week and 3 lessons per week throughout the 8-week intervention (25 lessons in total). Healthy Hearts aimed to build exercise intention by highlighting the benefits of PA and encouraging goal-setting and self-monitoring. The program was built based on the Multi-Process Action Control (M-PAC) framework. M-PAC addresses the intention-behavior gap through the understanding that ongoing reflective processes (ie, affective attitude and perceived opportunity) and regulation processes (behavioral and cognitive tactics to maintain intention focus) are necessary for one’s intention to become active and that the maintenance of behavior is supported by habit and identity, which can be categorized as reflexive processes [
Similar to previous “pay-per-minute” studies [
As previously mentioned, the SFII employed in this had similarities to the structure of a social impact bond. It differs in that the participants in the hypertension prevention program acted as both investors and as recipients of the program (eg, the hypertension prevention program). Further, this incentive program encouraged adherence to a PA program by having participants commit a mock investment through a contract. The SFII for this study follows a 6-step structure, broken down into the following (
Self-funded investment incentive.
Participants were given the same education program as the PPM group. However, the financial incentive differed. Participants in this intervention arm signed a mock contract committing to invest CAD $400 into their health for the duration of the 8-week program. No money was taken from the participants; however, they were encouraged to put this money aside for the duration of the study. Participants received a percentage of return on this initial investment based on the number of weeks they successfully met the Canadian PA guidelines, as recorded by their Fitbit. If a participant in this group met the goal for 0-2 weeks of the intervention, they received a 0% return. If a participant met the goals for 3-4 weeks of the intervention, they received a 1.5% return on this investment, which is equivalent to CAD $6. If a participant met their goal for 5-7 weeks of the intervention, they received a 3% return on investment or CAD $12. Lastly, the maximum return on investment is 5% or CAD $20, and this was rewarded if the participant met the goal for all 8 weeks of the intervention. A 5% investment return was chosen based on the annualized S&
To match the weekly intervention delivery frequency, participants received 1 email per week with contents from the web-based source HealthLinkBC [
The recruitment rate was calculated by dividing the number of individuals who enrolled in the study by the number of individuals who were eligible to enroll. This value was then divided by the number of months of recruitment [
Lesson completion data were downloaded from the Pathverse Admin portal (Pathverse Inc). Engagement was defined by the number of lessons that the intervention groups completed through the Pathverse app. There are a total of 25 lessons in the program.
Acceptability was measured postintervention through virtual semistructured interviews between the participant and the researcher. Thematic analysis was conducted to analyze and report themes from the semistructured interviews [
Fitbit devices [
Step data were downloaded throughout the intervention from the individual’s Fitbit account. The validity and reliability of using Fitbit to measure daily steps have been previously been established [
Self-report BP was collected. Participants were emailed instructions on how to measure their BP, per HT Canada to self-report an average of their 3 most recent BP measurements [
The Behavioral Regulation in Exercise Questionnaire (BREQ-3) [
The entire study was conducted digitally due to the COVID-19 pandemic. Interested individuals responded to a Facebook ad and were then contacted to arrange an initial web-based eligibility meeting. This first eligibility meeting was no longer than 30 minutes. Once the consent form was signed and returned, a baseline meeting was scheduled, and a Fitbit Inspire 2 [
At the virtual baseline meeting, participants completed the baseline questionnaire (demographic information and the BREQ-3 [
Descriptive statistics were used to determine the feasibility (recruitment, engagement, and acceptability) of an 8-week mobile-based PPM and SFII hypertension prevention program. The follow-up semistructured interviews were analyzed using thematic analysis (ie, overall positive and negative comments and future program changes) [
The changes in MVPA, daily steps, SBP, DBP, and RAI were analyzed using an intention-to-treat approach [
Consolidated standards of reporting trials flow diagram outlining participant recruitment is shown in
Two participants in the PPM financial incentive group discontinued the intervention, 1 dropped out and stopped syncing their Fitbit, and 1 dropped out due to an injury not related to the study. One participant in the SFII group dropped out and stopped syncing their Fitbit. All participants (n=18, 100%) allocated to the control arm successfully completed the intervention and follow-up meetings.
CONSORT (Consolidated Standards of Reporting Trials) flow diagram of enrolment, allocation, follow-up, and analysis. PA: physical activity; PPM: pay-per-minute; SFII: self-funded investment incentive.
Baseline demographics and PA levels are presented in
Baseline demographics.
Variable | PPMa (n=19) | SFIIb (n=18) | CONc (n=18) | ||||||
Age (years), mean (SD) | 55.4 (5.70) | 55.8 (6.17) | 55.1 (6.43) | .95 | |||||
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.47 | ||||||||
|
Male | 3 (16) | 1 (6) | 1 (6) |
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Female | 16 (84) | 17 (94) | 17 (94) |
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.15 | ||||||||
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Caucasian | 19 (100) | 18 (100) | 17 (94) |
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South Asian | 0 (0) | 0 (0) | 1 (6) |
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.60 | ||||||||
|
Some high school | 0 (0) | 1 (6) | 0 (0) |
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||||
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High school graduate | 2 (11) | 3 (16) | 4 (22) |
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Some college or university | 3 (15) | 0 (0) | 0 (0) |
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College or university degree | 10 (53) | 7 (39) | 9 (50) |
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Graduate degree or higher | 4 (21) | 7 (39) | 5 (28) |
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.38 | ||||||||
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$15,000-$29,999 | 1 (6) | 1 (6) | 0 (0) |
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||||
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$30,000-$49,999 | 1 (6) | 2 (11) | 1 (6) |
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||||
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$50,000-$74,999 | 3 (17) | 4 (22) | 2 (11) |
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$75,000-$99,999 | 2 (11) | 5 (28) | 4 (22) |
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$100,000-$150,000 | 7 (39) | 2 (11) | 6 (33) |
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$150,000+ | 4 (22) | 4 (22) | 4 (22) |
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|
.33 | ||||||||
|
Married or living with partner | 12 (63) | 11 (61) | 15 (83) |
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Single or living alone | 4 (21) | 2 (11) | 1 (6) |
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Single or living with others | 3 (16) | 5 (28) | 2 (11) |
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MVPAe (min/week), mean (SD) |
217.0 (199.3) | 131.8 (157.1) | 258.5 (148.8) | .09 | |||||
Daily steps, mean (SD) | 7367 (3095) | 7106 (3358) | 7789 (2806) | .80 | |||||
SBPf (mm Hg), mean (SD) | 125.2 (12.0) | 123.0 (10.9) | 121.7 (12.5) | .80 | |||||
DBPg (mm Hg), mean (SD) | 80.8 (8.3) | 77.5 (9.9) | 77.80 (9.9) | .67 | |||||
RAIh score, mean (SD) | 15.7 (2.4) | 14.6 (2.4) | 15.75 (2.3) | .32 |
aPPM: pay-per-minute.
bSFII: self-funded investment incentive.
cCON: control.
dAt the time of writing: CAD $1=US $0.74.
eMVPA: moderate-to-vigorous physical activity.
fSBP: systolic blood pressure.
gDBP: diastolic blood pressure.
hRAI: relative autonomy index.
With recruitment taking place over 5 weeks, the recruitment rate was 77%. Thus, the screening-to-enrollment ratio dictated that 95% of those eligible did enroll in the study, with a total of 55 participants that provided consent. Throughout the 8-week intervention, there was a 95% retention rate, with 52 of 55 randomized participants completing the study.
Engagement was analyzed for the PPM and SFII arms, as the control group did not have access to the Healthy Hearts program. Lessons were presented on a completion basis, meaning you had to complete the previous lesson to unlock the next. Overall, 65% of all Healthy Hearts lessons were completed (63% for PPM and 67% for SFII).
A total of 52 participants (PPM: n=17; SFII: n=17; CON: n=18) completed the semistructured interview at the follow-up meeting. The main themes that emerged were positive and negative feelings about the intervention and user design of the mobile app.
The user-friendliness of the app was mentioned by most who used it (PPM n=13; SFII n=15), with positive comments relating to the usability and system interface. Ten participants mentioned that 3 lessons per week were adequate. Generally, the content was well accepted. The control group, who received weekly emails, also gave positive feedback on the variety of content received. When asked about the impact of the program on their PA, 30 participants commented on Fitbit, citing how it was a useful tool to see their daily activity.
Participants in the SFII group were asked if they would have been willing to give their own money toward their contract. A minority of participants (6/17, 32%) mentioned that they would not have been comfortable investing their own money into a PA program. Of those who said yes to investing CAD $400 into their health with a guarantee to be given the money back after 8 weeks, 86% of participants reported a gross income of greater than CAD $75,000 per year. Of those that said no to investing their own money for the duration of the program, 75% reported earning less than CAD $75,000 gross annual income.
While the user interface of the app was appreciated, some participants (n=3) did not find all the lessons necessary for them. Three different participants mentioned that they wanted more guidance with how much they were earning each week in the program, either through email or through the app.
For MVPA at 4 weeks, both PPM and SFII showed medium effect size differences, relative to control (PPM vs control: η2p=0.06, mean 117.8, SD 514 minutes; SFII vs control: η2p=0.08, mean 145.3, SD 616 minutes). However, for MVPA, at 8 weeks SFII showed a medium effect relative to control (η2p=0.07), while small effects were observed for PPM relative to control (η2p=0.003). This translates to a mean increase in MVPA by 22.8 (SD 249) minutes per week for PPM relative to control. Meanwhile, SFII intervention showed a mean increase of 113.8 (SD 256) minutes per week relative to control. Relative to baseline, 70% (n=26) of those were meeting the Canadian PA guidelines in both financial incentive arms.
Relative to the control for daily steps, both PPM and SFII showed a small effect with changes in daily steps at both 4 (PPM η2p=0.02, mean Δdaily steps 937, SD 2039; SFII η2p≤0.001, mean Δdaily steps 274, SD 2043) and 8 weeks (PPM: η2p=0.02 mean Δdaily steps −27, SD 2362; SFII: η2p≤0.001, mean Δdaily steps −144, SD 2367) (
Changes in physical activity outcomes at 4 weeks and 8 weeks relative to baseline.
|
PPMa (n=19), mean (SD) | SFIIb (n=18), mean (SD) | CONc (n=18), mean (SD) | 4 weeks | 8 weeks | ||||||||||||
|
Δ 4w | Δ 8w | Δ 4w | Δ 8w | Δ 4w | Δ 8w | Overall |
PPM vs CON, η2pd | SFII vs CON, η2p | PPM vs SFII, η2p | Overall |
PPM vs CON, η2p | SFII vs CON, η2p | PPM vs SFII, η2p | |||
MVPAe (minutes) | 117.9 (316.0) | 20.6 (201.7) | 144.8 (236.7) | 149.2 (214.3) | −31.6 (122.4) | −20.7 (134.2) | .08 |
|
|
<0.001 | .15 | <0.001 |
|
0.05 | |||
Daily steps | 950 (2329) | −7 (2887) | 352 (1839) | −23 (1962) | 221 (2274) | 183 (2906) | .54 | 0.02 | <0.001 | 0.02 | .83 | <0.001 |
|
<0.001 |
aPPM: pay-per-minute.
bSFII: self-funded investment incentive.
cCON: control.
dη2p: partial eta squared.
eMVPA: moderate-to-vigorous physical activity.
fItalics indicate at least a medium effect in partial eta squared values.
Relative to the control, SBP decreased in the SFII intervention group (η2p=0.001; ΔSBP −0.4, SD 1.4 mm Hg) but increased in the PPM intervention (η2p=0.12; ΔSBP 7.1, SD 23.6 mm Hg). Similarly, relative to the control, DBP decreased in the SFII intervention group (η2p=0.02, ΔDBP −2.31, SD 7.66 mm Hg) but increased in the PPM intervention (η2p=0.04; ΔDBP 3.55, SD 6.25 mm Hg).
Changes in blood pressure and physical activity motivation at 8 weeks relative to baseline.
|
PPMa (n=19), mean (SD) | SFIIb (n=18), mean (SD) | CONc (n=18), mean (SD) | Overall |
PPM vs CON, η2pd | SFII vs CON, η2p | PPM vs SFII, η2p |
|
Δ8w | Δ8w | Δ8w |
|
|
|
|
SBPe (mm Hg) | 1.4 (5.5) | −5.5 (8.5) | −4.8 (12.3) | .08 |
|
<0.001 |
|
DBPg (mm Hg) | 0.2 (4.9) | −4.0 (6.9) | −1.9 (11.8) | .17 | 0.04 | 0.02 |
|
RAIh | −2.8 (3.6) | −3.9 (2.5) | −3.3 (3.3) | .27 | <0.001 | 0.03 | 0.05 |
aPPM: pay-per-minute.
bSFII: self-funded investment incentive.
cCON: control.
dη2p: partial eta squared.
eSBP: systolic blood pressure.
fItalics indicate at least a medium effect in partial eta squared values.
gDBP: diastolic blood pressure.
hRAI: relative autonomy index.
At the 8-week follow-up, the PPM arm decreased their score by 0.3 (SD 1.4; η2p=0.01) relative to the control, and the SFII arm decreased their score by 1.3 (SD 4.3; η2p=0.03) relative to the control. These reductions translate to a small effect size.
The primary objective of this study was to determine the feasibility (recruitment, engagement, and acceptability) of an 8-week mobile-based PPM and SFII hypertension prevention program. The secondary objectives of this study were to explore the effects of PPM and SFII interventions relative to the control on improving PA levels, BP, and PA motivation following the intervention. To our knowledge, this is the first mobile app intervention to compare the PPM and SFII financial incentive arms, relative to a control group. Overall, the findings from this study support a future efficacy trial in line with Phase III of the ORBIT model [
Based on previous research [
Throughout the 8-week intervention, there was a 95% retention rate, with 52 of 55 randomized participants completing the study. An 80-100% retention rate is indicative of a strong trial [
Previous research has shown that maintaining engagement over time is a challenge in many mHealth interventions [
Overall, positive feedback was received on the program. Both objective usage metrics and subjective experiences with the Healthy Hearts program delivered using the Pathverse platform showed that adults were highly engaged with this intervention. Many commented that completing 3 lessons per week was an adequate amount that did not overwhelm them. These findings are all indicators of the acceptability of the intervention to this demographic.
The study results supported the hypothesis that those in the PPM or SFII arms, relative to control, would show a small-to-moderate effect size in improving MVPA and daily steps at 4 and 8 weeks, respectively. Small-to-moderate effect sizes have been documented for overall increases in PA in previous financial incentive and PA studies [
Although we did not ask participants to commit to investing their own money in the SFII group, over 68% of the participants in the study said that they are willing to invest their own money. Participants found the 5% return from SFII acceptable. This is important to the feasibility of the investment-based SFII model proposed in this study since several stock index funds over the last 30 years have shown an average return between 5% and 8% [
Contrary to our hypothesis, participants in the PPM and SFII groups did not show a small-to-moderate reduction in SBP and DBP, relative to the control. Previous studies of similar length have reported a significant reduction in SBP and DBP by −3.8 mm Hg (95% CI−5.63 to−2.06 mm Hg;
Finally, it was hypothesized that those in the PPM and SFII arm would increase their autonomous motivation due to receiving an 8-week hypertension education program and receiving a modest incentive. However, the results of this study did not align with our hypothesis. The design of this program encouraged competence development in promoting reaching attainable PA goals, a strategy that has the potential to increase intrinsic motivation through the self-determination theory [
There were several study limitations. First, the participants were primarily Caucasian, with higher education, and with most earning above CAD $100,000 annually, well above the median income for British Columbians [
This study examined the feasibility of an 8-week SFII and PPM financial incentive mHealth intervention to improve PA and collected both quantitative and qualitative data. Feasibility results indicated high recruitment and retention rates, engagement, and acceptability. Preliminary results showed PPM and SFII showed a small-to-medium effect in improving MVPA and steps relative to the control. SFII may have the potential to be more sustainable than a PPM financial incentive model due to the nature of the self-funding incentive. It is recommended that this framework of financial incentive be explored in practice with participants investing their own money for the duration of the intervention, opposed to a mock contract agreement. Overall, the results from this study support recommendations for a future full-scale RCT in line with Phase III of the ORBIT model [
CONSORT-eHEALTH checklist (V 1.6.1).
blood pressure
Behavioral Regulation in Exercise Questionnaire
diastolic blood pressure
mobile health
multiprocess action control
moderate-to-vigorous physical activity
physical activity
pay-per-minute
relative autonomy index
randomized controlled trial
systolic blood pressure
self-funded investment incentive
The authors gratefully acknowledge the contributions of the participants in this study. The authors are also grateful for the support of the Mitacs Research Training Award and the BC Support Unit Patient-Oriented Research Fellowship.
The data sets generated and analyzed during the current study are available from the corresponding author on reasonable request.
None declared.