All participants received smartphone-connected, wireless glucometers. The control arm received no further intervention. The intervention arm received daily financial incentives for the 3-month incentive period. These incentives were removed in the 3-month follow-up period.
The solid vertical line represents the end of the incentive period and start of the follow-up period.
eTable 1. Study HbA1c Intervals in Weeks
eTable 2. Adjusted Difference in HbA1c for With and Without Imputed Data
eFigure 1. HbA1c by Arm at Baseline, 3 Months and 6 Months
eFigure 2. Change in HbA1c at 3 Months by Adherence to Daily Glucose Monitoring Goals
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Wong CA, Miller VA, Murphy K, et al. Effect of Financial Incentives on Glucose Monitoring Adherence and Glycemic Control Among Adolescents and Young Adults With Type 1 Diabetes: A Randomized Clinical Trial. JAMA Pediatr. 2017;171(12):1176–1183. doi:10.1001/jamapediatrics.2017.3233
Do daily financial incentives improve adherence to daily glucose monitoring goals and glycemic control among adolescents and young adults with type 1 diabetes during a 3-month intervention?
In a randomized clinical trial including 90 adolescents and young adults with poorly controlled type 1 diabetes, daily financial incentives improved glucose monitoring in the intervention group (50.0%) vs the control group (18.9%) but did not affect their glycemic control.
Financial incentives showed promise for improving glucose monitoring behaviors among adolescents and young adults with type 1 diabetes.
Glycemic control often deteriorates during adolescence and the transition to young adulthood for patients with type 1 diabetes. The inability to manage type 1 diabetes effectively during these years is associated with poor glycemic control and complications from diabetes in adult life.
To determine the effect of daily financial incentives on glucose monitoring adherence and glycemic control in adolescents and young adults with type 1 diabetes.
Design, Setting, and Participants
The Behavioral Economic Incentives to Improve Glycemic Control Among Adolescents and Young Adults With Type 1 Diabetes (BE IN CONTROL) study was an investigator-blinded, 6-month, 2-arm randomized clinical trial conducted between January 22 and November 2, 2016, with 3-month intervention and follow-up periods. Ninety participants (aged 14-20) with suboptimally controlled type 1 diabetes (hemoglobin A1c [HbA1c] >8.0%) were recruited from the Diabetes Center for Children at the Children’s Hospital of Philadelphia.
All participants were given daily blood glucose monitoring goals of 4 or more checks per day with 1 or more level within the goal range (70-180 mg/dL) collected with a wireless glucometer. The 3-month intervention consisted of a $60 monthly incentive in a virtual account, from which $2 was subtracted for every day of nonadherence to the monitoring goals. During a 3-month follow-up period, the intervention was discontinued.
Main Outcomes and Measures
The primary outcome was change in HbA1c levels at 3 months. Secondary outcomes included adherence to glucose monitoring and change in HbA1c levels at 6 months. All analyses were by intention to treat.
Of the 181 participants screened, 90 (52 [57.8%] girls) were randomized to the intervention (n = 45) or control (n = 45) arms. The mean (SD) age was 16.3 (1.9) years. The intervention group had significantly greater adherence to glucose monitoring goals in the incentive period (50.0% vs 18.9%; adjusted difference, 27.2%; 95% CI, 9.5% to 45.0%; P = .003) but not in the follow-up period (15.3% vs 8.7%; adjusted difference, 3.9%; 95% CI, −2.0% to 9.9%; P = .20). The change in HbA1c levels from baseline did not differ significantly between groups at 3 months (adjusted difference, −0.08%; 95% CI, −0.69% to 0.54%; P = .80) or 6 months (adjusted difference, 0.03%; 95% CI, −0.55% to 0.60%; P = .93).
Conclusions and Relevance
Among adolescents and young adults with type 1 diabetes, daily financial incentives improved glucose monitoring adherence during the incentive period but did not significantly improve glycemic control.
clinicaltrials.gov Identifier: NCT02568501
Glycemic control in type 1 diabetes often deteriorates during adolescence and the transition to young adulthood with increased risks of acute and long-term complications.1,2 This poor control is attributed to difficulties with adhering to the prescribed medical regimen.2-4 These challenges occur in the context of decreasing parental involvement and developing psychosocial maturity.5-7 As young people prepare to transition to adult models of care that require independent self-management skills, interventions that empower them to successfully manage chronic disease can improve outcomes.6
Daily glucose monitoring is fundamental to achieving glycemic control in type 1 diabetes since glucose level awareness dictates insulin dose adjustment, eating behaviors, and physical activity. A number of interventions have targeted increased monitoring as a means of achieving better control.3,8,9 However, many interventions in adolescents and young adults that utilized family-related interventions, motivational interviews, text messages, and training in diabetes management skills have demonstrated relatively small effects (eg, mean effect of 0.5% drop in hemoglobin A1c [HbA1c]).3,10,11
Behavioral economics is a field of study that applies economic and psychological principles, such as immediate gratification and loss aversion, to overcome barriers to behavior change. Behavioral economic interventions utilizing financial incentives have been used to increase adherence to chronic disease management regimens in adult populations but have not yet been widely tested in adolescents and young adults.12-16 One feasibility trial with 51 adolescents and young adults with type 1 diabetes established acceptability, feasibility, and preliminary efficacy of increased monitoring with financial incentives that were contingent or noncontingent on meeting glucose monitoring goals.17 Two small studies (17 and 10 participants) without control groups used incentives (eg, $0.10 for each test with a bonus for 4 checks per day) for glucose testing in youth; both studies showed improved glucose monitoring adherence and HbA1c levels.18,19 Financial incentives have been proposed but have infrequently been tested in other adolescent health domains, such as exercise, nutrition, sexual health, and preventive behaviors for sun exposure and smoking.12,16,20-25 To our knowledge, no study has tested loss-aversion incentives among adolescents and young adults for self-monitoring behaviors.
In this randomized clinical trial, we sought to determine among adolescents and young adults with type 1 diabetes if daily financial incentives could improve adherence to daily glucose monitoring goals and glycemic control. To monitor adherence and provide incentives in real time, we used wireless glucometer devices, which are readily accepted by people in this age group.26 Such devices allow remote self-monitoring with minimal additional effort, especially when combined with enhanced engagement strategies, such as financial incentives.13,27 Home-based monitoring is particularly attractive for adolescents and young adults who tend to access outpatient care less frequently.28,29
The Behavioral Economic Incentives to Improve Glycemic Control Among Adolescents and Young Adults With Type 1 Diabetes (BE IN CONTROL) study was a 6-month randomized clinical trial conducted between January 22 and November 2, 2016, with 3-month intervention and follow-up periods. We enrolled 90 participants who were randomly assigned to an incentive intervention or control arm. The protocol is reported in Supplement 1. The Children’s Hospital of Philadelphia and The University of Pennsylvania institutional review boards approved this study. All participants provided electronic informed consent (≥18 years) and/or assent (14-17 years) with parental permission. Participants received $20 for enrolling and $30 if they completed the HbA1c monitoring and surveys at the end of the intervention and follow-up periods.
Quiz Ref IDParticipants were aged 14 to 20 years and had received care for type 1 diabetes for at least 1 year at the Children’s Hospital of Philadelphia Diabetes Center for Children. Those with suboptimal glycemic control (defined as most recent HbA1c>8.0% [to convert to percentage of total Hb, multiply by 0.01]) were eligible if they had email access, had a smartphone, and were English speaking.
Participants were recruited between October 27, 2015, and May 6, 2016, by emailing and/or posting letters to all patients aged 14 to 20 years with type 1 diabetes who received care at the Children’s Hospital of Philadelphia (approximately 1160 people), as well as by contacting them by telephone or in person at their diabetes care visits. They were excluded if they were participating in another interventional trial. At enrollment, participants completed a survey assessing sociodemographic information and baseline type 1 diabetes characteristics. They also completed scales on diabetes-related self-efficacy, treatment adherence, and family and friend support.30-33
Way to Health is an automated technology platform based at the University of Pennsylvania that was used for study enrollment, randomization, surveying, communication via text or email, and intervention delivery and data capture.34 Participants were randomly assigned to the control or incentive group using a block size of 6 and stratified by baseline HbA1c (8.0%-10.0% vs >10.0%). All investigators, statisticians, and data analysts were blinded to group assignments until the end of the study and all analyses. Participants and the study coordinator could not be blinded to arm assignment.
All participants were given daily blood glucose monitoring goals of 4 glucose level checks per day (separated by ≥2 hours) with at least 1 reading within the target range (70-180 mg/dL per the American Diabetes Association [to convert to millimoles per liter, multiply by 0.0555]).35 We incentivized a within-range blood glucose reading to encourage monitoring and appropriate responses to high glucose level readings.
Each participant was given a glucometer (iHealth Smart Wireless Gluco-Monitoring System; iHealth) and test strips for the duration of the study. This glucometer syncs with a smartphone application via Bluetooth. Participants were enrolled only after they synced their first glucose level reading.
Quiz Ref IDWe designed the daily financial incentives as loss framed based on prior work on the motivating potential of loss aversion.15,36-40 Participants randomized to the intervention arm were credited $60 in a virtual account at the beginning of each month during the 3-month (13-week) incentive period; they lost $2 for each day of nonadherence to the glucose monitoring goals. Intervention arm participants received daily monitoring and incentive feedback during the incentive period by email or text message (per their preference). For example, “You met your glucose monitoring goals yesterday. Keep it up! You have $60 remaining in your account,” or “Sorry, you did not meet your glucose monitoring goal yesterday (at least 4 checks with 1 in target range). You lost $2 from your account. Remaining balance = $58.” Participants in the intervention arm received their remaining virtual account balance at the end of each incentive month on a reloadable debit card. The incentives were discontinued during the follow-up period.
Participants obtained an HbA1c level within 3 weeks of the end of the intervention (at 3 months) and follow-up (at 6 months) periods, most often during their usual diabetes clinic visits. Online surveys were administered at the end of the intervention and follow-up periods.
In addition, a sample of 20 intervention arm participants were interviewed via telephone after completing the study. Semistructured interviews included questions on financial incentives, connected glucometers, and study feedback. Interviews were recorded and transcribed. Responses to the semistructured interview questions were analyzed using thematic content analysis by 2 of us (C.A.W. and A.M.) independently.41
Quiz Ref IDThe primary outcome measure was the change in HbA1c levels at 3 months compared with baseline. Secondary outcome measures included adherence to daily glucose monitoring goals during the incentive and follow-up periods and change in HbA1c levels at 6 months vs baseline. Adherence to daily glucose monitoring goals was measured as the mean proportion of participant-days achieving the daily blood glucose monitoring goals. Themes from the interviews were identified.
A priori sample size calculations were based on a clinically relevant HbA1c difference of 1.0 between the intervention and control groups. Assuming an HbA1c SD of 1.5, power of 0.80, 2-sided significance of P = .05, and 20% dropout rate, we estimated a sample of 90 participants (45 per arm).
For each participant on each day of the study (participant-day level), we obtained their glucose level readings. Data could be missing for any day if a participant did not use the study glucometer, although patients had the opportunity to manually enter readings from other glucometers (eg, at school). Manually entered glucose level readings (18% of all study readings) were tracked, and no suspicious patterns for cheating were detected. We dichotomized the data at the participant-day level to create a binary variable indicating that the participant achieved the daily blood glucose monitoring goals or did not. Using this binary variable, we estimated the mean proportion of participant-days achieving the goal for the group of participants in each study group during the intervention and follow-up periods and for each week during the study. All randomly assigned participants were included in the intention-to-treat analysis.
Mean change in HbA1c levels from baseline was calculated by arm at 3 and 6 months in separate unadjusted and adjusted models. In the adjusted model, we fit a prespecified generalized linear regression for the change in HbA1c level, controlling for the same baseline type 1 diabetes and demographic characteristics listed above plus calendar month fixed effects and interval from baseline to 3- and 6-month HbA1c levels (eTable 1 in Supplement 2). We used multiple imputation to generate values for participants missing 3-month (n = 5) and 6-month (n = 11) HbA1c level measurements with the following predictors in 5 imputations: study arm, baseline HbA1c level, 3- or 6-month HbA1c level, demographics (same as in adjusted analyses), baseline type 1 diabetes measures/scales (HbA1c level, insulin regimen, number of daily glucose checks, complications, hypoglycemic event frequency, self-efficacy scale, adherence to diabetes regimen scale, and diabetes support scale), and calendar month. Results were combined using the Rubin standard rules.42 The imputed analyses were qualitatively similar to the nonimputed analyses (eTable 2 in Supplement 2). The correlation between adherence quartiles and change in HbA1c levels was evaluated by Kruskal-Wallis tests by study arm.
We estimated the unadjusted proportion of participant-days adherent to the blood glucose monitoring goals for each arm and the difference between the means for the 2 arms for the incentive period, the follow-up period, and for each week during the study.
In adjusted analyses, the prespecified main generalized linear model for the differences between arms in adherence to blood glucose monitoring goals controlled for baseline diabetes (baseline HbA1c level, insulin regimen) and demographic (sex, age, race/ethnicity, living situation, insurance coverage, and household income) characteristics and calendar month fixed effects. Bootstrap methodology, which resampled participants within each arm 150 times, was used to construct the 95% CIs for the probability of achieving the goals.43
All statistical analyses were performed using R, version 3.2.3 (R Foundation). All hypothesis tests were 2-sided, and a significance level of P = .05 was used.
We enrolled 90 participants (Figure 1). Among the 91 youths assessed for eligibility but not randomized, age and baseline HbA1c levels were available for 55 and 76 participants, respectively. The mean age of nonenrolled (16.5 years) and enrolled (16.3 years) participants were similar, and the mean HbA1c level of nonenrolled participants was lower (8.63%), in part because HbA1c ≤8.0% was the most common inclusion criteria not met.
The majority of participants identified as white non-Hispanic and were full-time students, covered by private insurance, and living with family (Table 1). The mean baseline HbA1c level was 9.88% in the control arm and 9.84% in the intervention arm.
The proportion of participant-days achieving the glucose monitoring goals during the 3-month incentive period was 18.9% in the control group vs 50.0% in the intervention group (adjusted difference, 27.2%; 95% CI, 9.5% to 45.0%; P = .003) (Table 2). Adherence to glucose monitoring goals decreased in both groups during the follow-up period (Figure 2). Rates of adherence were 8.7% and 15.3% in the follow-up period for the control and intervention groups, respectively (adjusted difference, 3.9%; 95% CI, −2.0% to 9.9%; P = .20) (Table 2). The percentage of days without any glucometer readings during the incentive period was 46.3% and 25.3% for the control and intervention arms, respectively, compared with 75.0% in the control arm and 65.8% in the intervention arm in the follow-up period. Most nonadherent days in both groups (>85%) were due to an insufficient number of glucose level checks; 10% to 15% of the days were nonadherent because none of at least 4 checks was within the goal range.
Quiz Ref IDThe HbA1c level decreased from 9.88% to 9.44% in the control group and from 9.84% to 9.27% for the intervention group at 3 months (eFigure 1 in Supplement 2). The change in the HbA1c level was not statistically significant when comparing the intervention and control groups from baseline to 3 months (adjusted difference, −0.08%; 95% CI, −0.69% to 0.54%; P = .80) or 6 months (adjusted difference, 0.03%; 95% CI, −0.55% to 0.60%; P = .93) (Table 2). We also found no significant correlation between quartiles of adherence to glucose monitoring and change in HbA1c levels (eFigure 2 in Supplement 2).
Participants in the intervention group had positive feedback on the feasibility of daily financial incentives and mixed perspectives on the ideal incentive amount and structure (Table 3). Those who favored loss aversion incentives were motivated by the loss of money that they believed was already theirs and the cumulative money lost for repeated nonadherent days. While some believed gain incentives (ie, winning money for meeting the daily monitoring goals) would have been better, others proposed alternative incentive structures, such as bonuses (“If you had a week of not losing any money, maybe get an extra couple bucks just for a reward.”) or what another called “a multiplier effect” (“The first day you would lose $2.00 and the second day you could lose $4.00. So, if you continue to miss, it would rise at an exponential level.”). Others mentioned that the extrinsic financial rewards helped them to realize the intrinsic value of taking care of their type 1 diabetes.
When asked about what study components were helpful, the most common response from both arms (36% of participants) was the connected glucometers and smartphone application. Participants liked tracking, interpreting, and sharing glucose readings on the application (Table 3).
Participants noted that glucose monitoring incentives did not always motivate other behaviors necessary for improved glycemic control, such as appropriate responses to high glucose level readings or accurate carbohydrate counting. Other HbA1c-relevant issues that participants identified were insulin regimen changes and life stressors (eg, busy school semester).
In our study of adolescents and young adults with type 1 diabetes, financial incentives showed promise for improving diabetes self-monitoring behaviors. Daily financial incentives were effective in increasing adherence to blood glucose monitoring goals during the incentive period, but this adherence did not lead to an improvement in glycemic control. Those exposed to the daily incentives were more than twice as likely to meet their daily blood glucose monitoring goals. These improvements are noteworthy given that eligibility was limited to youth with poor control, who have historically been difficult to engage in treatment.44
This is one of the first studies to demonstrate that financial incentives for adolescents and young adults can motivate behavior change. Our participants identified the loss aversion financial incentives, particularly the cumulative losses, as important in motivating their increased daily blood glucose monitoring. While we based the loss aversion structure and amount of $2 per day on prior work in adults, further research is needed to determine how financial incentives might best be tailored to young people.15,27,36-39 For example, other financial incentive structures, such as those suggested by participants (eg, multiplier effect), may be more effective in sustaining the effect in the incentive and follow-up periods.
Unique opportunities exist for implementing financial incentives in youth, who are often financially dependent on others. For example, parents could allow a desired privilege (eg, later curfew) or purchase (eg, cell phone data plan) contingent on meeting type 1 diabetes care goals. Financial incentives may also be effective for behaviors critical for other chronic health conditions in youth, such as medication adherence in those who have received transplants or have asthma.
Increased daily blood glucose monitoring with the requirement that at least 1 level per day be within the target range did not translate to significant decreases in HbA1c levels. These monitoring goals may not have been sufficiently stringent to achieve an effect on HbA1c. In general, achieving substantial improvements in glycemic control has been challenging across multicomponent interventions promoting adherence in individuals with type 1 diabetes.10,11
In contrast to prior studies, we did not identify a correlation between blood glucose monitoring frequency and glycemic control.3,8,9 Participants identified several factors that they believed had a greater effect on HbA1c than adherence to glucose monitoring (eg, inadequate responses to high glucose levels, schedule predictability). The multifactorial influences on glycemic control suggest that future studies should test incentivizing both the process (eg, glucose monitoring with more readings within the goal range) and the outcome (eg, HbA1c level improvement). Adding social incentives (eg, social networks, relative social ranking) to the intervention could further improve outcomes; diabetes adherence promotion interventions that targeted behavioral (eg, blood glucose monitoring) and social processes were more potent in a meta-analysis.10
In our study, the increased level of blood glucose monitoring more rapidly declined after the incentives were removed. While longer-term habit formation is the ultimate goal, preventing serious health deterioration from chronic disease would be a valuable intermediate accomplishment for adolescents and young adults, who are in a developmentally critical transition period.2,45
Although this study did not test the effect of smartphone-connected glucometers, participants in both arms were generally positive about the devices. These glucometers with automated data entry and aggregation on an application may contribute to empowering and educating participants. Given ubiquitous smartphone use, connected glucometers could make self-management more convenient and engaging for young people with type 1 diabetes.26
Quiz Ref IDOur findings should be viewed in light of several limitations. The small sample size from a single site may limit generalizability and subgroup analyses, for example, by race/ethnicity or socioeconomic status.46 Participants were also required to have a smartphone, although more than three-quarters of adolescents and young adults have access to a smartphone.47 The differences in adherence to daily glucose monitoring goals may be explained in part by missing glucose level readings if participants used other glucometers. However, our qualitative data suggest that participants in both arms valued the study glucometer’s features and could manually enter glucose level readings if needed. Finally, the intervention included email or text notifications. Given the daily loss-framed incentive design, it was not possible to disentangle the effects of incentives and messaging. Nonetheless, many participants stated that the financial incentives, in and of themselves, were motivating.
The inability to manage type 1 diabetes effectively during the adolescent and young adult years is associated with poor glycemic control and complications in adult life.48 Identifying interventions that empower young people to manage their disease effectively is crucial. Financial incentives and smartphone-connected glucometers proved to be promising tools that deserve further exploration in adolescents and young adults with type 1 diabetes.
Accepted for Publication: July 8, 2017.
Corresponding Author: Charlene A. Wong, MD, MSHP, Department of Pediatrics, Duke Clinical Research Institute, Duke-Margolis Center for Health Policy, Duke University, 100 Fuqua Dr, Box 90120, Durham, NC 27708 (email@example.com).
Published Online: October 23, 2017. doi:10.1001/jamapediatrics.2017.3233
Author Contributions: Dr Wong had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Wong, Miller, Ford, Willi, Patel.
Acquisition, analysis, or interpretation of data: Wong, Miller, Murphy, Small, Willi, Feingold, Morris, Ha, Zhu, Wang, Patel.
Drafting of the manuscript: Wong, Patel.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Wong, Small, Willi, Zhu, Wang, Patel.
Obtained funding: Wong, Patel.
Administrative, technical, or material support: Murphy, Willi, Feingold, Morris, Ha, Patel.
Study supervision: Wong, Miller, Ford, Willi, Feingold, Patel.
Conflict of Interest Disclosures: Dr Patel is also a principal at Catalyst Health, a technology and behavior change consulting firm.
Funding/Support: Dr Patel is supported by career development awards from the Department of Veterans Affairs HSR&D and the Doris Duke Charitable Foundation. The project described was supported in part by Grant Number UL1TR000003 from the National Center for Advancing Translational Science. The study was also supported in part by the Institute for Translational Medicine and Therapeutics at the University of Pennsylvania and the Division of Adolescent Medicine at the Children’s Hospital of Philadelphia.
Role of the Funder/Sponsor: None of the funders were involved in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Advancing Translational Science or the National Institutes of Health.