Another Trial Shows No Benefit From Fitbits, Even With Cash Bonus

  Liam Davenport

October 06, 2016

Activity trackers have only a moderate effect on physical-exercise levels and do not appear to improve health outcomes, even in the presence of cash incentives, indicate new findings from a study in Singapore.

Eric Finkelstein, PhD, MHA, professor, health services and systems research program, Duke-NUS Medical School, Singapore, and colleagues found that activity trackers were associated with increases in the number of minutes per week of moderate to vigorous physical activity (MVPA) but not with improvements in outcomes such as body mass index (BMI) and cardiorespiratory fitness.

Intriguingly, cash incentives tied to the number of steps taken per week initially improved physical-activity levels, but once they were stopped, individuals who had received them showed a relative decrease in exercise, to levels below those seen in people who had never received any such incentives.

"Our findings suggest that coupling the incentives to daily steps may not be the way to go. However, tying them to MVPA or aerobic steps is worth considering, as these are the type of steps most likely to improve health," Dr Finkelstein said in a press release.

"Yet the results also suggest that any incentive strategy would need to be in place for a longer period of time to generate any noticeable improvements in health benefits and to avoid any undermining effect from their removal," he added.

The results, which were published online by Lancet Diabetes & Endocrinology on October 4, are underlined by those from a recent randomized controlled trial assessing the impact of wearing technologies on BMI. As reported by Medscape Medical News, the use of trackers to measure diet and exercise in that trial did not improve weight loss compared with standard advice on physical activity and diet.

Little Evidence That Activity Trackers Can Improve Health Outcomes

In their paper, Dr Finkelstein and colleagues note that, despite their popularity, there is little concrete evidence that activity trackers can improve health outcomes. In a bid to explore this phenomenon, they recruited 800 full-time employees to their study (TRIPPA) from 13 organizations in Singapore who were aged 21 to 65 years and could walk at least 10 continuous steps.

The participants were randomly assigned to receive a Fitbit Zip activity tracker (n = 203), the tracker plus charity incentives (n = 199), the tracker plus cash incentives (n = 197), or no tracker but information about physical activity (control; n = 201).

Control and tracker-only participants received a weekly participation payment of SGD4 (about $3.00), regardless of the number of steps recorded. The incentive groups received SGD15 (about $11.00) every week that they logged 50,000 to 70,000 steps or SGD30 (about $22.00) if they recorded more than 70,000 steps, which they either donated to a charity of their choice (charity incentive) or kept themselves (cash incentive).

After 6 months,the cash- and charity-incentive groups both showed significant improvements in physical activity over control participants, at an additional 29 MVPA bout minutes per week (P = .0024) and 21 MVPA bout minutes per week (P = .0310), respectively.

The difference in physical activity between the tracker-only and control group, at 16 MVPA bout minutes per week, was not significant (P = .0854), with control individuals showing a reduction in activity.

Notably, the increase in activity in the cash- and charity-incentive groups was not significantly greater than that seen in the tracker-only group.

At 12 months, both the tracker-only and charity-incentive groups had significant improvements in physical activity over control participants, at an additional 37 MVPA bout minutes per week (P = .0001) and 32 MVPA bout minutes per week (P = .0013), respectively.

In contrast, there was no significant difference between the cash-incentive and control groups, at an increase of 15 MVPA bout minutes per week (P = .1363). Indeed, the cash-incentive group showed a significant reduction in physical activity vs the tracker-only group, at a decrease of 23 MVPA bout minutes per week (P = .0184).

None of the activity changes corresponded to health-outcome improvements, with no significant changes in body mass index, systolic blood pressure, cardiorespiratory fitness, or quality of life recorded.

Confusion About Nature of Activity Trackers

Discussing the findings, Dr Finkelstein told Medscape Medical News that there is "confusion" about the nature of activity trackers. He said: "In my opinion, pedometers and these types of things are measurement tools.

"I don't think that they're really interventions or even motivations per se, yet I think a lot of people think they are. [They think] that all you need is to put on these on, and suddenly you're going to be more active or weigh less."

He added: "In my mind, once you understand that these are just measurement tools, then it makes sense as to why they cease to have much value, because, once you wear them for a couple of days or weeks you know what they tell you and their usefulness dries out."

In contrast, incentives are "extrinsic motivations and now you use the Fitbit or something to, essentially, measure whether or not you met the goal."

Where it does get interesting — "and we can think about the psychology" — is the finding that, at 12 months, the cash-incentive group did worse than the tracker-only group, he observed.

"It suggests that there's an undermining effect — that giving someone a reward and taking it away is worse than doing nothing."

Dr Finkelstein pointed out that around a third of the literature on using behavior-change incentives to form good routines suggests that a habit can be induced, while the rest indicates that "if you give someone an incentive, they'll do more of that thing; if you take it away, they'll go back to their old ways."

While the findings revealed the undermining effect of incentives, Dr Finkelstein believes that "the bigger issue to me is not so much that people got worse but that as soon as you take the effect away, you lose the benefit."

"So to me what it says is that, if you find an incentive strategy that you like, you'd better stick with it."

Key Considerations for Future Research

In a Comment accompanying the Singapore study, Courtney M Monroe, PhD, from the Arnold School of Public Health and Technology Center to Promote Healthy Lifestyles, University of South Carolina, Columbia, describes it as "a large and important step forward for research into physical-activity promotion."

She said: "Future incentive-based studies targeting physical activity should include measures of motivation and examine how different aspects of these approaches can be manipulated to positively affect intrinsic motivation and physical activity in a cost-effective manner."

Dr Monroe also noted that the "absence of large, health-improving increases in physical activity" in this trial points to further avenues for study.

"Continuing to explore which aspects of physical activity should be targeted to elicit changes that will result in positive health outcomes and gaining a better understanding of who might benefit the most from wearables and financial incentives are key considerations for future research."

This study was supported by a Health Services Research Competitive research grant from the Ministry of Health, Singapore. The authors report no relevant financial relationships.

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Lancet Diabetes Endocrinol. Published online October 4, 2016. Abstract, Editorial

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