A Subsidized Healthy Food Prescription Program for Adults with type 2 Diabetes who are Experiencing Food Insecurity: Protocol for a Randomized Controlled Trial, Modelling and Implementation Studies
Authors: Olstad Dana Lee , Beall Reed F , Spackman Eldon , Dunn Sharlette , Lipscombe Lorraine , Williams Kienan , Oster Richard T , Scott Sara , Zimmermann Gabrielle L , McBrien Kerry A , St Kieran JD , Chan Catherine B , Tyminski Sheila , Berkowitz Seth A , Edwards Alun L , Saunders-Smith Terry , Tariq Saania , Popeski Naomi , White Laura , Williamson Tyler , L’Abbe Mary R , Raine Kim D , Nejatinamini Sara , Naser Aruba , Basualdo-Hammond Carlota , Norris Colleen , O’Connell Petra , Seidel Judy , Cabaj Jason , Campbell David JT 
Published: February 2021

Abstract
Background: The high cost of many healthy foods poses a significant challenge to the maintenance of optimal blood glucose levels for adults with type 2 diabetes (T2DM) who are experiencing food insecurity, leading to diabetes complications and excess acute care usage and costs. Subsidized healthy food prescription programs may help to reduce food insecurity by financially supporting patients to improve their diet quality, prevent diabetes complications and avoid acute care use. This study will use a type 2 hybrid effectiveness-implementation design to examine the reach, effectiveness, adoption, implementation and maintenance (RE-AIM) of a subsidized healthy food prescription program for adults who are experiencing food insecurity and persistent hyperglycemia. A randomized controlled trial (RCT) will investigate program effectiveness via impact on blood glucose levels (primary outcome), food insecurity, diet quality and other clinical and patient-reported outcomes. A modelling study will estimate longer-term program effectiveness in reducing diabetes-related complications, resource use and costs. An implementation study will examine all RE-AIM domains, including reasons behind program successes and failures, fidelity, mechanisms of impact, contextual determinants of effective implementation and sustainability. Methods: 404 adults who are experiencing food insecurity and persistent hyperglycemia, including adults who identify as Indigenous, will be randomized to a subsidized healthy food prescription intervention (n=202) or a healthy food prescription comparison group (n=202). Both groups will receive a healthy food prescription. The intervention group will additionally receive $1.50/day/household member to purchase healthy foods in supermarkets for 6 months. The implementation process will follow the Quality Implementation Framework. Outcomes will be assessed at baseline and follow-up (6 months) in the RCT and analyzed using mixed-effects linear and multinomial logistic/ordinal regression models. Longer-term outcomes will be modelled using the validated UK Prospective Diabetes Study outcomes simulation model-2. Implementation processes and outcomes will be continuously measured via quantitative and qualitative data and analyzed using descriptive statistics and theory-informed directed content analysis, respectively. Discussion: This research will provide a comprehensive body of data with high internal and external validity to assist policymakers and practitioners to effectively and rapidly translate the evidence generated into programs and policies to support patients with T2DM who are experiencing food insecurity. Trial registration: ClinicalTrials.gov NCT04725630 (January 25, 2021; https://www.clinicaltrials.gov/ct2/show/NCT04725630?term=Subsidized+Healthy+Food+Prescription+Program&cond=Diabetes+Mellitus%2C+Type+2&draw=2&rank=1).