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Randomised controlled trial of alternative messages to increase enrolment in a healthy food programme among individuals with diabetes
  1. A Gopalan1,2,
  2. J Paramanund3,
  3. P A Shaw4,5,
  4. D Patel3,
  5. J Friedman5,6,
  6. C Brophy7,
  7. A M Buttenheim5,8,
  8. A B Troxel5,9,
  9. D A Asch1,5,6,10,
  10. K G Volpp1,5,6,10
  1. 1Corporal Michael J. Cresencz VA Medical Center, Philadelphia, Pennsylvania, USA
  2. 2Division of Research, Kaiser Permanente Northern California, Oakland, California, USA
  3. 3Discovery Vitality, Johannesburg, South Africa
  4. 4Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  5. 5LDI Center for Health Incentives and Behavioral Economics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  6. 6Departments of Medicine and Medical Ethics and Health Policy, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  7. 7Vitality USA, New York, New York, USA
  8. 8Department of Community and Family Health, University of Pennsylvania School of Nursing, Philadelphia, Pennsylvania, USA
  9. 9Department of Population Health, NYU School of Medicine, New York, New York, USA
  10. 10Department of Health Care Management, Wharton School, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  1. Correspondence to Dr A Gopalan; Anjali.Gopalan{at}


Objectives We compared the effectiveness of diabetes-focused messaging strategies at increasing enrolment in a healthy food programme among adults with diabetes.

Methods Vitality is a multifaceted wellness benefit available to members of Discovery Health, a South Africa-based health insurer. One of the largest Vitality programmes is HealthyFood (HF), an incentive-based programme designed to encourage healthier diets by providing up to 25% cashback on healthy food purchases. We randomised adults with type 2 diabetes to 1 of 5 arms: (1) control, (2) a diabetes-specific message, (3) a message with a recommendation of HF written from the perspective of a HF member with diabetes, (4) a message containing a physician's recommendation of HF, or (5) the diabetes-specific message from arm 2 paired with an ‘enhanced active choice’(EAC). In an EAC, readers are asked to make an immediate choice (in this case, to enrol or not enrol); the pros and cons associated with the preferred and non-preferred options are highlighted. HF enrolment was assessed 1 month following the first emailed message.

Results We randomised 3906 members. After excluding those who enrolled in HF or departed from the Vitality programme before the first intervention email, 3665 (94%) were included in a modified intent-to-treat analysis. All 4 experimental arms had significantly higher HF enrolment rates compared with control (p<0.0001 for all comparisons). When comparing experimental arms, the diabetes-specific message with the EAC had a significantly higher enrolment rate (12.6%) than the diabetes-specific message alone (7.6%, p=0.0016).

Conclusions Messages focused on diabetes were effective at increasing enrolment in a healthy food programme. The addition of a framed active choice to a message significantly raised enrolment rates in this population. These findings suggest that simple, low-cost interventions can enhance enrolment in health promoting programmes and also be pragmatically tested within those programmes.

Trial registration number NCT02462057.

  • health promotion
  • messaging
  • active choice

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  • Contributors All the listed authors have met the requirements for authorship. AG, the lead author, was responsible for overseeing study conception and design, communication between team members, data analysis and interpretation, manuscript construction and manuscript revision. JP, DP and CB, who are all affiliated with Vitality, were responsible for day-to-day study operations (eg, sending of the email messages and abstracting enrolment data from internal Vitality tracking systems to send to the Penn team). Given their affiliations with Vitality, the study's funder, JP, DP and CB were not involved with data analysis and interpretation and only provided general feedback on the manuscript (ie, they had no influence on how findings were presented and interpreted). PAS, the study's lead biostatistician, oversaw all statistical planning, data transfer from the Vitality team, data analysis and interpretation, and provided critical feedback on the manuscript. JF and AMB contributed to study conception and design, result interpretation, and provided detailed feedback on the manuscript. ABT and DAA contributed content expertise in the areas of biostatistics and behavioural economics, respectively, and both were actively involved in manuscript preparation. KGV served as the principal investigator on the study. He contributed his significant expertise in behavioural economics and randomised interventions to study conception and design, data interpretation and manuscript construction. KGV is the guarantor of this manuscript.

  • Funding The study was funded by an unconditional award from Vitality USA.

  • Disclaimer The study topic, research question and study design were at the discretion of the lead author and not the funder. Though several Vitality USA and Discovery Vitality employees were involved in helping to operationalise the study, these individuals were not involved in data analysis or interpretation and only provided general feedback on the manuscript (ie, had no control over how findings were presented and interpreted).

  • Competing interests PAS, ABT and KGV have received research funding from the Vitality Institute. JP and DP are employees of Discovery Vitality, and CB is an employee of Vitality USA. Given these relationships, these three individuals were not involved in data analysis but provided only operational support and expertise. DAA and KGV are both principals at the behavioural economics consulting firm, VAL Health. KGV also has received consulting income from CVS Caremark and research funding from Humana, CVS Caremark, Discovery (South Africa), Hawaii Medical Services Association and Merck. ABT serves on the scientific advisory board of VAL.

  • Ethics approval University of Pennsylvania IRB and the University of Witwatersrand Ethics Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data are available.

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