Effects of Mobile-Based Financial Incentive Interventions for Adults at Risk of Developing Hypertension: Feasibility Randomized Controlled Trial (Preprint)

Abstract

BACKGROUND Hypertension (HT) 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 are not meeting PA guidelines. Financial incentive interventions have the power to increase PA levels but are often limited due to cost. Further, mHealth 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. OBJECTIVE (1) Determine the feasibility (recruitment, engagement, acceptability) of an 8-week mobile-based PPM and SFII HT prevention PA program, and (2) explore the effects of PPM and SFII interventions relative to control on PA levels, BP, and PA motivation. METHODS 55 adults aged 40-65 not meeting the Canadian PA Guidelines were randomized into the following groups: financial incentive groups, PPM or SFII, receiving up to $20 each, or a control group without financial incentive. Feasibility outcome measures (recruitment, engagement, acceptability) were assessed. Secondary outcomes included changes in PA outcomes (MVPA, 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 (RAI) relative to baseline were compared among the groups at follow-up. RESULTS 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 control at 4 weeks, the PPM and SFII arms increased their MVPA with medium effect (PPM vs. control: η2p=.06, mean 117.8, SD 514 minutes; SFII vs control: η2p=.08, mean 145.3, SD 616 minutes). At 8 weeks, PPM maintained a small effect is MVPA relative to control (η2p<.01, mean 22.8, SD 249 minutes) and SFII displayed a medium effect size (η2p=.07, mean 113.8, SD 256 minutes). Small effects were observed for PPM and SFII relative to control for SBP and DBP (PPM: η2p=.12, mean SBP 7.1, SD 23.61 mmHg; η2p=.04, mean DBP 3.5, SD 6.2 mmHg; SFII: η2p<.01, mean SBP −0.4, SD 1.4 mmHg; η2p=.02, mean DBP −2.3, SD 7.7 mmHg) and RAI (PPM: η2p<.01, SFII: η2p=.03). CONCLUSIONS The recruitment, engagement, and acceptability results suggest that future full-scale RCT examining the efficacy of PPM and SFII relative to control is feasible. Studies with longer duration are warranted.