Obesity
Conditions
Keywords
weight loss, financial incentives, internet weight loss
Brief summary
The investigators propose a randomized controlled trial to evaluate whether the addition of financial incentives to a high-quality, online behavioral weight loss intervention produces better weight losses than the online treatment alone.
Detailed description
Overweight and obese but otherwise healthy participants (N=416) will be recruited in approximately equal numbers at two clinical centers, the University of South Carolina and the University of Vermont. Eligible participants will be randomized to one of two conditions: 1) an 18-month, 36-session group Internet behavioral weight control treatment (Internet Only) which replicates the intervention the investigators have implemented previously; or 2) the same 18-month, 36-session group Internet treatment plus financial incentives for performance of 3 key self-management behaviors (Internet+ Incentive). Both conditions will have access to the same web-based intervention platform and the same counselor-delivered intervention elements; the presence of economic incentives for behavioral and weight goals is the only difference between the conditions. Assessments will be conducted at Baseline, 2, 6, 12 and 18 months. Cost data will be collected to inform cost effectiveness evaluations.
Interventions
BEHAVIORALInternet Only
18 month behavioral weight loss intervention delivered online
BEHAVIORALInternet + Incentives
18 month behavioral weight loss intervention delivered online with the possibility of earning incentives for losing weight and performing weight loss behaviors including monitoring food intake, exercising, and daily weighing
Sponsors
University of South Carolina
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
University of Vermont
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* over 18 * BMI between 25 and 50 * Not currently pregnant or pregnant in the previous 6 months and currently breastfeeding or planning on becoming pregnant in 18 months * Have a computer at home or at work with flashplayer, access to the internet, and a smart phone (to allow use of step counting aps) * Free of medical problems that might contraindicate participation in a behavioral weight reduction program containing an exercise component * Not enrolled in another weight reduction program * Not currently on medication that would affect weight loss
Exclusion criteria
* had a heart attack or stroke in the previous six months * had weight loss surgery * lost 10 pounds or more in the previous 6 months * currently taking medications for weight loss * required by their doctor to follow a special diet (other than low fat) * planning to move out of the area within 18 months * schedule conflicts making it difficult to attend online chats * live more than 60 minutes driving distance from either University of South Carolina or University of Vermont campuses
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Weight Change | 6 months | Weight will be measured at baseline, 2, 6 months. Weight loss at 6 months will be calculated as kg lost from baseline. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Class Attendance | 6 months | Average number of classes attended |
| Self Monitoring of Body Weight | 6 months | Number of days with body weight self reported |
| Dietary Intake Self Monitoring | 6 months | Number of days reported dietary intake over 6 months |
| Self Monitoring of Physical Activity | 6 months | Number of days physical activity reported |
| Steps/Day | 6 months | Number of Steps/day |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Internet Only Participants will be required to attend a weekly Internet chat session with your group members and one of the behavioral weight control therapists. Participants will learn the principles of managing eating and exercise behaviors in weekly, hour-long chat sessions and by completing weekly lessons. Participants are asked to self-monitor foods and exercise through the use of a smartphone ap. Participants will wear a tracking device that monitors steps. All participants will be contacted via e-mail individually, by their group leader who will monitor their progress and offer advice and encouragement. Meetings are weekly for 24 weeks and monthly for 12 months.
Internet Only: 18 month behavioral weight loss intervention delivered online | 212 |
| Internet + Incentives Participants are given the same intervention as described for the internet only group, with the exception that they will have the opportunity to earn financial incentives. Financial incentives will be based on participants weight loss, and compliance with certain weight loss behaviors including meeting exercise goals, self-monitoring foods consumed, and daily weighing and reporting.
Internet + Incentives: 18 month behavioral weight loss intervention delivered online with the possibility of earning incentives for losing weight and performing weight loss behaviors including monitoring food intake, exercising, and daily weighing | 206 |
| Total | 418 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Lost to Follow-up | 38 | 15 |
| Overall Study | Pregnancy | 1 | 3 |
| Overall Study | Withdrawal by Subject | 1 | 0 |
Baseline characteristics
| Characteristic | Internet Only | Total | Internet + Incentives |
|---|---|---|---|
| Age, Continuous | 48 years STANDARD_DEVIATION 11.14 | 49 years STANDARD_DEVIATION 11.11 | 50 years STANDARD_DEVIATION 11.01 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 2 Participants | 6 Participants | 4 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 210 Participants | 412 Participants | 202 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Asian | 1 Participants | 2 Participants | 1 Participants |
| Race (NIH/OMB) Black or African American | 63 Participants | 107 Participants | 44 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 1 Participants | 1 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 147 Participants | 307 Participants | 160 Participants |
| Region of Enrollment United States | 212 participants | 418 participants | 206 participants |
| Sex: Female, Male Female | 194 Participants | 381 Participants | 187 Participants |
| Sex: Female, Male Male | 18 Participants | 37 Participants | 19 Participants |
| Weight | 97.8 kilograms STANDARD_DEVIATION 19.5 | 96.7 kilograms STANDARD_DEVIATION 17.7 | 95.6 kilograms STANDARD_DEVIATION 15.9 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 212 | 0 / 206 |
| other Total, other adverse events | 0 / 212 | 0 / 206 |
| serious Total, serious adverse events | 0 / 212 | 0 / 206 |
Outcome results
Primary
Weight Change
Weight will be measured at baseline, 2, 6 months. Weight loss at 6 months will be calculated as kg lost from baseline.
Time frame: 6 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Internet Only | Weight Change | Baseline | 97.8 kilograms | Standard Deviation 19.5 |
| Internet Only | Weight Change | 6 Months | 4.7 kilograms | Standard Deviation 6.6 |
| Internet + Incentives | Weight Change | 6 Months | 6.4 kilograms | Standard Deviation 5.5 |
| Internet + Incentives | Weight Change | Baseline | 95.6 kilograms | Standard Deviation 15.9 |
Comparison: The study was designed to detect a 2.2-kg group weight loss difference between groups with a standard deviation of 5.8 kg,4,5 a 5% Type I error rate, and 80% power. To adjust for possible clustering effects in this nested design, the adjusted variance estimate was increased to 7.67, calculated using a conservative intraclass correlation coefficient of 0.05.p-value: <0.01Mixed Models Analysis
Secondary
Class Attendance
Average number of classes attended
Time frame: 6 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Internet Only | Class Attendance | 16 Number of classes attended | Standard Deviation 6.6 |
| Internet + Incentives | Class Attendance | 18 Number of classes attended | Standard Deviation 5.1 |
Secondary
Dietary Intake Self Monitoring
Number of days reported dietary intake over 6 months
Time frame: 6 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Internet Only | Dietary Intake Self Monitoring | 85 Number of days dietary intake reported | Standard Deviation 54 |
| Internet + Incentives | Dietary Intake Self Monitoring | 119 Number of days dietary intake reported | Standard Deviation 44 |
Secondary
Self Monitoring of Body Weight
Number of days with body weight self reported
Time frame: 6 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Internet Only | Self Monitoring of Body Weight | 72 Number of days weight self report | Standard Deviation 51 |
| Internet + Incentives | Self Monitoring of Body Weight | 115 Number of days weight self report | Standard Deviation 43 |
Secondary
Self Monitoring of Physical Activity
Number of days physical activity reported
Time frame: 6 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Internet Only | Self Monitoring of Physical Activity | 85 Number of days Physical Activity report | Standard Deviation 54 |
| Internet + Incentives | Self Monitoring of Physical Activity | 118 Number of days Physical Activity report | Standard Deviation 44 |
Secondary
Steps/Day
Number of Steps/day
Time frame: 6 months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Internet Only | Steps/Day | 7447 number of steps | Standard Deviation 2888 |
| Internet + Incentives | Steps/Day | 8057 number of steps | Standard Deviation 2672 |