The design and conduct of Keep It Off: An online randomized trial of financial incentives for weight-loss maintenance

Testing the missing at random assumption in generalized linear models in the presence of instrumental variables

Practical problems with missing data are common, and many methods have been developed concerning the validity and/or efficiency of statistical procedures. On a central focus, there have been longstanding interests on the mechanism governing data missingness, and correctly deciding the appropriate mechanism is crucially relevant for conducting proper practical investigations. In this paper, we present a new hypothesis testing approach for deciding between the conventional notions of missing at random and missing not at random in generalized linear models in the presence of instrumental variables. The foundational idea is to develop appropriate discrepancy measures between estimators whose properties significantly differ only when missing at random does not hold. We show that our testing approach achieves an objective data-oriented choice between missing at random or not. We demonstrate the feasibility, validity, and efficacy of the new test by theoretical analysis, simulation studies, and a real data analysis.

Quantifying and correcting bias due to outcome dependent self-reported weights in longitudinal study of weight loss interventions

In response to the escalating global obesity crisis and its associated health and financial burdens, this paper presents a novel methodology for analyzing longitudinal weight loss data and assessing the effectiveness of financial incentives. Drawing from the Keep It Off trial-a three-arm randomized controlled study with 189 participants-we examined the potential impact of financial incentives on weight loss maintenance. Given that some participants choose not to weigh themselves because of small weight change or weight gains, which is a common phenomenon in many weight-loss studies, traditional methods, for example, the Generalized Estimating Equations (GEE) method tends to overestimate the effect size due to the assumption that data are missing completely at random. To address this challenge, we proposed a framework which can identify evidence of missing not at random and conduct bias correction using the estimating equation derived from pairwise composite likelihood. By analyzing the Keep It Off data, we found that the data in this trial are most likely characterized by non-random missingness. Notably, we also found that the enrollment time (i.e., duration time) would be positively associated with the weight loss maintenance after adjusting for the baseline participant characteristics (e.g., age, sex). Moreover, the lottery-based intervention was found to be more effective in weight loss maintenance compared with the direct payment intervention, though the difference was non-statistically significant. This framework's significance extends beyond weight loss research, offering a semi-parametric approach to assess missing data mechanisms and robustly explore associations between exposures (e.g., financial incentives) and key outcomes (e.g., weight loss maintenance). In essence, the proposed methodology provides a powerful toolkit for analyzing real-world longitudinal data, particularly in scenarios with data missing not at random, enriching comprehension of intricate dataset dynamics.

Effect of Financial Incentives and Environmental Strategies on Weight Loss in the Healthy Weigh Study: A Randomized Clinical Trial

IMPORTANCE

Modest weight loss can lead to meaningful risk reduction in adults with obesity. Although both behavioral economic incentives and environmental change strategies have shown promise for initial weight loss, to date they have not been combined, or compared, in a randomized clinical trial.

OBJECTIVE

To test the relative effectiveness of financial incentives and environmental strategies, alone and in combination, on initial weight loss and maintenance of weight loss in adults with obesity.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial was conducted from 2015 to 2019 at 3 large employers in Philadelphia, Pennsylvania. A 2-by-2 factorial design was used to compare the effects of lottery-based financial incentives, environmental strategies, and their combination vs usual care on weight loss and maintenance. Interventions were delivered via website, text messages, and social media. Participants included adult employees with a body mass index (BMI; weight in kilograms divided by height in meters squared) of 30 to 55 and at least 1 other cardiovascular risk factor. Data analysis was performed from June to July 2021.

INTERVENTIONS

Interventions included lottery-based financial incentives based on meeting weight loss goals, environmental change strategies tailored for individuals and delivered by text messages and social media, and combined incentives and environmental strategies.

MAIN OUTCOME AND MEASURES

The primary outcome was weight change from baseline to 18 months, measured in person.

RESULTS

A total of 344 participants were enrolled, with 86 participants each randomized to the financial incentives group, environmental strategies group, combined financial incentives and environmental strategies group, and usual care (control) group. Participants had a mean (SD) age of 45.6 (10.5) years and a mean (SD) BMI of 36.5 (7.1); 247 participants (71.8%) were women, 172 (50.0%) were Black, and 138 (40.1%) were White. At the primary end point of 18 months, participants in the incentives group lost a mean of 5.4 lb (95% CI, -11.3 to 0.5 lb [mean, 2.45 kg; 95% CI, -5.09 to 0.23 kg]), those in the environmental strategies group lost a mean of a 2.2 lb (95% CI, -7.7 to 3.3 lb [mean, 1.00 kg; 95% CI, -3.47 to 1.49 kg]), and the combination group lost a mean of 2.4 lb (95% CI, -8.2 to 3.3 lb [mean, 1.09 kg; 95% CI, -3.69 to 1.49 kg]) more than participants in the usual care group. Financial incentives, environmental change strategies, and their combination were not significantly more effective than usual care. At 24 months, after 6 months without an intervention, the difference in the change from baseline was similar to the 18-month results, with no significant differences among groups.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, across all study groups, participants lost a modest amount of weight but those who received financial incentives, environmental change, or the combined intervention did not lose significantly more weight than those in the usual care group. Employees with obesity may benefit from more intensive individualized weight loss strategies.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02878343.

Efficacy of telehealth acceptance and commitment therapy for weight loss: a pilot randomized clinical trial

Telehealth coaching for weight loss has high population-level reach but limited efficacy. To potentially improve on this limitation, the purpose of this study was to determine the preliminary efficacy of the first known telephone coaching acceptance and commitment therapy (ACT) intervention for weight loss. A two-arm, stratified, individually randomized pilot trial comparing ACT (n = 53) with standard behavioral therapy (SBT; n = 52) was used for this study. Both interventions were delivered in 25 telephone coaching calls (15-20 min each) over a 12 month period. Weight was measured at baseline and 3, 6, and 12 month postrandomization follow-ups. Recruited from 32 U.S. states, participants were of mean age 40.7, 42% male, 34% racial/ethnic minority, and mean baseline body mass index of 34.3. Fractions of 10% or more scale-reported weight loss: 15% for ACT versus 4% for SBT at 3 month follow-up (N = 86; odds ratio [OR] = 4.61; 95% confidence interval [CI]: 0.79, 26.83), 24% for ACT versus 13% for SBT at 6 month follow-up (N = 72; OR = 2.45; 95% CI: 0.65, 9.23), 30% for ACT versus 30% for SBT at 12 month follow-up (N = 57; OR = 0.93; 95% CI: 0.28, 3.09). Fractions of 10% or more self-reported weight loss at 12 month follow-up: 25% for ACT versus 15% for SBT (N = 75; OR = 2.38; 95% CI: 0.68, 8.34). The conclusion of the study was the preliminary evidence that telephone coaching ACT may be efficacious for weight loss.

Sustaining the reach of a scalable weight loss intervention through financial incentives- a pragmatic, feasibility, online randomized trial protocol

BACKGROUND

High attrition following initial enrollment in evidence-based weight loss programs is a common, challenging, and under-studied issue. A behavioral economics approach consisting of modest monetary incentives may help to engage participants beyond enrollment to close the initial attrition gap.

PURPOSE

To describe the methods and design of a pragmatic, online randomized controlled trial (RCT) of an incentivized, technology-facilitated weight loss program through an innovative research-practice partnership involving primary care, health promotion researchers, and a small business.

METHODS

This study is a four-arm (1:1:1:1) RCT that compares the efficacy of outcome-based (weight loss), process-based (weighing in), a combination of outcome- and process-based, or choice-based incentives on sustaining program reach after initial enrollment for an evidence-based weight loss program. The multicomponent weight loss program includes a website, social cognitive theory-based daily health coaching, tailored messaging delivered via email and text messaging, access to online health coaches, and objective weight assessment through a community kiosk. The study will enroll 400 individuals aged 19 and older who have a body mass index ≥25 kg/m², and have reliable access to the Internet or a smart phone. Participants will be followed for 3, 6, 9, and 12 months to assess program reach and representativeness, and continued participation after enrollment. The secondary outcomes include weight loss and program implementation costs. We will conduct participant focus groups to understand the barriers and facilitators of participation and key informant interviews focusing on clinic managers and care providers to explore the potential for future adoption and implementation of the evidence-based program.

DISCUSSION

This study possesses the potential to close the attrition gap after initial enrollment in a web-based digital weight loss intervention in the primary care and community settings. Clinicaltrials.gov registration: NCT04225234.

Evidence and Challenges for Translation and Population Impact of the Diabetes Prevention Program

PURPOSE OF REVIEW

Type 2 diabetes is common, burdensome, and preventable. Landmark trials such as the Diabetes Prevention Program (DPP) demonstrated that resource-intensive lifestyle support interventions resulting in modest weight loss via healthy diet changes and physical activity can lower the rate of diabetes development by 58%. We performed a review of efforts to translate and implement DPP-like programs throughout the USA to identify challenges and opportunities for improvement.

RECENT FINDINGS

For more than a decade, multiple stakeholders have worked to translate evidence-based principles of diabetes prevention to reach 84 million Americans with prediabetes. DPP-like programs have been delivered by over 1500 organizations, reaching almost 300,000 people, but this number represents less than 1% of the target population. Research has uncovered large gaps in efforts to diagnose, raise awareness, and provide access to DPP-like programs for adults with prediabetes, requiring further stakeholder engagement and coordination to resolve. Efforts to address prevailing gaps in diabetes prevention must address distinct and sometimes conflicting priorities and concerns of stakeholders. Our review recommends several areas of further research and action to improve type 2 diabetes prevention on a population scale.

Effect of Escalating Financial Incentive Rewards on Maintenance of Weight Loss: A Randomized Clinical Trial

IMPORTANCE

Identifying effective strategies for treating obesity is a public health priority.

OBJECTIVE

To test an escalating lottery-based incentive tied to daily self-weighing for weight loss maintenance.

DESIGN, SETTING, AND PARTICIPANTS

This 2-phase, 2-arm randomized clinical trial enrolled participants aged 30 to 80 years with an initial body mass index (calculated as weight in kilograms divided by height in meters squared) of 30.0 to 45.0 who lost at least 5 kg during 4 to 6 months in a national online weight management program. Study investigators and outcomes assessors were blinded to participant groups. Data were collected and analyzed from May 23, 2016, through November 13, 2017, based on intention to treat.

INTERVENTIONS

All participants were advised to weigh themselves daily, with a goal of 6 or more days per week, and received text messaging feedback on their performance. Incentive group participants were eligible for a lottery-based incentive worth an expected value of $3.98 in week 1 that escalated by $0.43 each week they achieved their self-weighing goal during months 1 to 6 (phase 1), followed by no incentives during months 7 to 12 (phase 2).

MAIN OUTCOMES AND MEASURES

The primary outcome was weight change at the end of phase 1. Secondary outcomes included weight change at the end of phase 2 and changes in self-reported physical activity and eating behaviors.

RESULTS

A total of 258 participants (128 in the incentive group and 130 in the control group) had a mean (SD) age of 48.0 (10.5) years and mean (SD) body mass index of 32.1 (3.9); 225 (87.2%) were women; 235 (91.1%) were white; and 102 (39.5%) had an annual income of at least $100 000. Weight measurement was transmitted by 250 participants (96.9%) at 6 months and 227 (88.0%) at 12 months. The percentage of weeks that incentive and control participants achieved a mean self-weighing of at least 6 times was 85.3% vs 75.8%, respectively (P = .002) in phase 1 and 37.7% vs 50.2%, respectively (P = .009) in phase 2. Mean weight changes at the end of phase 1 were -1.1 (95% CI, -2.1 to -0.1) kg in the incentive group and -1.9 (95% CI, -2.9 to -0.8) kg in the control group, with a mean difference of 0.7 (95% CI, -0.7 to 2.2) kg (P = .30 for comparison). At the end of phase 2, mean weight changes were 0.2 (95% CI, -1.2 to 1.7) kg in the incentive group and -0.6 (95% CI, -2.0 to 0.8) kg in the control group, with a mean difference of 0.8 (95% CI, -1.2 to 2.8) kg (P = .41 for comparison).

CONCLUSIONS AND RELEVANCE

Compared with an active control condition of weekly messages, escalating lottery-based incentives transiently increased rates of self-weighing but did not significantly enhance weight loss maintenance.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01900392.

Persuasive System Design Principles and Behavior Change Techniques to Stimulate Motivation and Adherence in Electronic Health Interventions to Support Weight Loss Maintenance: Scoping Review

BACKGROUND

Maintaining weight after weight loss is a major health challenge, and eHealth (electronic health) solutions may be a way to meet this challenge. Application of behavior change techniques (BCTs) and persuasive system design (PSD) principles in eHealth development may contribute to the design of technologies that positively influence behavior and motivation to support the sustainable health behavior change needed.

OBJECTIVE

This review aimed to identify BCTs and PSD principles applied in eHealth interventions to support weight loss and weight loss maintenance, as well as techniques and principles applied to stimulate motivation and adherence for long-term weight loss maintenance.

METHODS

A systematic literature search was conducted in PsycINFO, Ovid MEDLINE (including PubMed), EMBASE, Scopus, Web of Science, and AMED, from January 1, 2007 to June 30, 2018. Arksey and O'Malley's scoping review methodology was applied. Publications on eHealth interventions were included if focusing on weight loss or weight loss maintenance, in combination with motivation or adherence and behavior change.

RESULTS

The search identified 317 publications, of which 45 met the inclusion criteria. Of the 45 publications, 11 (24%) focused on weight loss maintenance, and 34 (76%) focused on weight loss. Mobile phones were the most frequently used technology (28/45, 62%). Frequently used wearables were activity trackers (14/45, 31%), as well as other monitoring technologies such as wireless or digital scales (8/45, 18%). All included publications were anchored in behavior change theories. Feedback and monitoring and goals and planning were core behavior change technique clusters applied in the majority of included publications. Social support and associations through prompts and cues to support and maintain new habits were more frequently used in weight loss maintenance than weight loss interventions. In both types of interventions, frequently applied persuasive principles were self-monitoring, goal setting, and feedback. Tailoring, reminders, personalization, and rewards were additional principles frequently applied in weight loss maintenance interventions. Results did not reveal an ideal combination of techniques or principles to stimulate motivation, adherence, and weight loss maintenance. However, the most frequently mentioned individual techniques and principles applied to stimulate motivation were, personalization, simulation, praise, and feedback, whereas associations were frequently mentioned to stimulate adherence. eHealth interventions that found significant effects for weight loss maintenance all applied self-monitoring, feedback, goal setting, and shaping knowledge, combined with a human social support component to support healthy behaviors.

CONCLUSIONS

To our knowledge, this is the first review examining key BCTs and PSD principles applied in weight loss maintenance interventions compared with those of weight loss interventions. This review identified several techniques and principles applied to stimulate motivation and adherence. Future research should aim to examine which eHealth design combinations can be the most effective in support of long-term behavior change and weight loss maintenance.

Log2Lose: Development and Lessons Learned From a Mobile Technology Weight Loss Intervention

Background

Providing financial incentives has gained popularity as a strategy to promote weight loss, but questions remain about how best to utilize them. A promising mobile health strategy provides users with near-real-time financial incentives based on both the process of weight loss (behavioral modification) and actual weight loss. To maximize the impact of this strategy, a methodology is needed to close the gap between the desired behavior and the financial incentive. Leveraging mobile health tools—such as mobile phone apps, cellular body weight scales that transmit data to physicians and researchers, and text messaging for instructions and encouragement—has the potential to close this gap.

Objective

This study aimed to describe the development of an innovative technology-based solution and lessons learned from a feasibility trial—Log2Lose—that encouraged individuals to lose weight by providing near-real-time financial incentives for weight loss and/or dietary self-monitoring.

Methods

We recruited participants (N=96) with a body mass index greater than or equal to 30 kg/m² for a 24-week weight loss trial. Participants received a behavioral intervention of biweekly, in-person group sessions and were instructed to log a minimum number of daily calories in MyFitnessPal and to step on the BodyTrace cellular scale at least twice per week. In a 2×2 design, participants were randomized into 4 groups to receive financial incentives for the following: (group 1) weekly weight loss and dietary self-monitoring, (group 2) dietary self-monitoring only, (group 3) weekly weight loss only, or (group 4) no financial incentives. Diet and weight data from the devices were obtained through application programming interfaces. Each week, we applied algorithms to participants’ data to determine whether they qualified for a monetary incentive (groups 1-3). A text message notified these participants of whether they met weight loss and/or self-monitoring requirements to earn an incentive and the amount they earned or would have earned. The money was uploaded to a debit card.

Results

Our custom-engineered software platform analyzed data from multiple sources, collated and processed the data to send appropriate text messages automatically, and informed study staff of the appropriate incentives. We present lessons learned from the development of the software system and challenges encountered with technology, data transmission, and participants (eg, lost connections or delayed communication).

Conclusions

With consistent and constant validation checks and a robust beta test run, the process of analyzing data and determining eligibility for weekly incentives can be mostly automated. We were able to accomplish this project within an academic health system, which required significant security and privacy safeguards. Our success demonstrates how this methodology of automated feedback loops can provide health interventions via mobile technology.

Trial Registration

ClinicalTrials.gov NCT02691260; https://clinicaltrials.gov/ct2/show/NCT02691260

The Healthy Weigh study of lottery-based incentives and environmental strategies for weight loss: Design and baseline characteristics

Identifying effective strategies for treating obesity is a clinical challenge and a public health priority. The present study is an innovative test of the relative effectiveness of lottery-based financial incentives and environmental strategies on weight loss and maintenance. The Healthy Weigh study is evaluating the comparative effectiveness of behavioral economic financial incentives and environmental strategies, separately and together, in achieving initial weight loss and maintenance of weight loss, in obese urban employee populations. Healthy Weigh is a multi-site, 4-arm randomized controlled trial (RCT) in which 344 employed participants were randomized to one of four arms. The study arms are: 1) standard employee wellness benefits and weigh-ins every 6 months (control arm/usual care); and the control/usual care plus either: 2) daily lottery incentives tied to achievement of weight loss goals (incentive arm); 3) individually tailored environmental strategies around food intake and physical activity (environmental arm); or 4) a combination of incentives and environmental strategies (combined arm). This trial used a web-based platform to enroll, communicate with, and track participant weight change. Wireless scales were used by participants in the three treatment group arms to digitally transmit daily/weekly weights. For females, the baseline median (interquartile range, IQR) for BMI and weight were 37.0 (33.5, 40.6) and 219.9 (198.1, 248.6), respectively; and for males, they were 36.0 (32.8, 39.8) and 247.9 (228.1, 279.5), respectively. The population was generally well-educated. This study demonstrated that multi-site employee-based recruitment for a weight-control intervention study is feasible but may need additional time for coordination between diverse environments.

Financial incentive strategies for maintenance of weight loss: results from an internet-based randomized controlled trial

Background/objective

Financial incentives can improve initial weight loss; we examined whether financial incentives can improve weight loss maintenance.

Subjects/methods

Participants aged 30–80 years who lost at least 5 kg during the first 4–6 months in a nationally available commercial weight loss program were recruited via the internet into a three-arm randomized trial of two types of financial incentives versus active control during months 1–6 (Phase I) followed by passive monitoring during months 7–12 (Phase II). Interventions were daily self-weighing and text messaging feedback alone (control) or combined with a lottery-based incentive or a direct incentive. The primary outcome was weight change 6 months after initial weight loss. Secondary outcomes included weight change 12 months after initial weight loss (6 months after cessation of maintenance intervention), and self-reported physical activity and eating behaviors.

Results

Of 191 participants randomized, the mean age was 49.0 (SD = 10.5) years and weight loss prior to randomization was 11.4 (4.7) kg; 92% were women and 89% were White. Mean weight changes during the next 6 months (Phase I) were: lottery −3.0 (5.8) kg; direct −2.8 (5.8) kg; and control −1.4 (5.8) kg (all pairwise comparisons p > 0.1). Weight changes through the end of 12 months post-weight loss (Phase II) were: lottery −1.8 (10.5) kg; direct −0.7 (10.7) kg; and control −0.3 (9.4) kg (all pairwise comparisons p > 0.1). The percentages of participants who maintained their weight loss (defined as gaining ≤1.36 kg) were: lottery 79%, direct 76%, and control 67% at 6 months and lottery 66%, direct 62%, and control 59% at 12 months (all pairwise comparisons p > 0.1). At 6 and 12 months after initial weight loss, changes in self-reported physical activity or eating behaviors did not differ across arms.

Conclusions

Compared with the active control of daily texting based on daily home weighing, lottery-based and direct monetary incentives provided no additional benefit for weight loss maintenance.

An online randomized controlled trial, with or without problem-solving treatment, for long-term cancer survivors after hematopoietic cell transplantation

PURPOSE

This randomized controlled trial examines the efficacy of INSPIRE, an INternet-based Survivorship Program with Information and REsources, with or without problem-solving treatment (PST) telehealth calls, for survivors after hematopoietic cell transplantation (HCT).

METHODS

All adult survivors who met eligibility criteria were approached for consent. Participants completed patient-reported outcomes at baseline and 6 months. Those with baseline impaired scores on one or more of the outcomes were randomized to INSPIRE, INSPIRE + PST, or control with delayed INSPIRE access. Outcomes included Cancer and Treatment Distress, Symptom Checklist-90-R Depression, and Fatigue Symptom Inventory. Planned analyses compared arms for mean change in aggregated impaired outcomes and for proportion of participants improved on each outcome.

RESULTS

Of 1306 eligible HCT recipients, 755 (58%) participated, and 344 (45%) had one or more impaired scores at baseline. We found no reduction in aggregated outcomes for either intervention (P > 0.3). In analyses of individual outcomes, participants randomized to INSPIRE + PST were more likely to improve in distress than controls (45 vs. 20%, RR 2.3, CI 1.0, 5.1); those randomized to INSPIRE alone were marginally more likely to improve in distress (40 vs. 20%, RR 2.0, CI 0.9, 4.5).

CONCLUSIONS

The INSPIRE online intervention demonstrated a marginal benefit for distress that improved with the addition of telehealth PST, particularly for those who viewed the website or were age 40 or older.

IMPLICATIONS FOR CANCER SURVIVORS

Online and telehealth programs such as INSPIRE offer opportunities to enhance HCT survivorship outcomes, particularly for mood, though methods would benefit from strategies to improve efficacy.

Acceptability of financial incentives for maintenance of weight loss in mid-older adults: a mixed methods study

BACKGROUND

Health insurers worldwide implement financial incentive schemes to encourage health-related behaviours, including to facilitate weight loss. The maintenance of weight loss is a public health challenge, and as non-communicable diseases become more prevalent with increasing age, mid-older adults could benefit from programs which motivate weight loss maintenance. However, little is understood about their perceptions of using financial incentives to maintain weight loss.

METHODS

We used mixed methods to explore the attitudes and views of participants who had completed an Australian weight loss and lifestyle modification program offered to overweight and obese health insurance members with weight-related chronic diseases, about the acceptability and usefulness of different types of financial incentives to support weight loss maintenance. An online survey was completed by 130 respondents (mean age = 64 years); and a further 28 participants (mean age = 65 years) attended six focus groups.

RESULTS

Both independent samples of participants supported a formalised maintenance program. Online survey respondents reported that non-cash (85.2%) and cash (77%) incentives would be potentially motivating; but only 40.5% reported that deposit contracts would motivate weight loss maintenance. Results of in-depth discussions found overall low support for any type of financial incentive, but particularly deposit contracts and lotteries. Some participants expressed that improved health was of more value than a monetary incentive and that they felt personally responsible for their own health, which was at odds with the idea of financial incentives. Others suggested ongoing program and peer support as potentially useful for weight loss maintenance.

CONCLUSIONS

If financial incentives are considered for mid-older Australian adults in the health insurance setting, program planners will need to balance the discordance between participant beliefs about the individual responsibility for health and their desire for external supports to motivate and sustain weight loss maintenance.