Veggie Rx: A pilot, 3-arm randomized controlled trial of a fruit and vegetable prescription program for patients with type two diabetes

Abstract. Consuming a nutrient-dense diet, rich in fruits and vegetables (F&Vs) is at the cornerstone of type 2 diabetes (T2DM) treatment. Yet, among Hispanic adults, only 16% meet the recommended minimum F&V intake recommendations and they have higher rates of T2DM than non-Hispanic whites (16.6% versus 13.3%, respectively). F&V Prescription (F&V Rx) programs are embedded in clinical settings, target medically high-risk patients such as those with T2DM, and provide them with vouchers to purchase F&V at local retailers. Preliminary F&V Rx studies in patients with T2DM have found F&V intake increases of 0.2-1.6 servings per day and hemoglobin A1c (A1c) reductions from 0.35-0.71% [3.8 -7.8 mmol/mol]. However, none of these studies included diabetes self-management education and support (DSME/S) which can lead to A1c decreases from 0.24% to 1.0% [2.6-10.9 mmol/mol]. Our team conducted a pilot F&V Rx study where we incentivized DSME/S attendance by providing a F&V Rx at each session. Although DSME/S uptake is typically very low after referral (around 5-7%), our program had a 73% first session attendance rate. Further, at 7 months post- program, we found a clinically- and statistically-significant reduction in A1c of 1.3% [14.2 mmol/mol] (p=.001). Although the receipt of the F&V Rx vouchers was contingent upon DSME/S attendance in our study, other T2DM-focused F&V Rx studies did not have DSME/S attendance requirements and they also saw A1c reductions. Thus, understanding the effect of a F&V Rx on DSME/S uptake and retention with and without attendance requirements is a key design issue that must be evaluated. This proposal is in response to PAS 20- 160 for short-term, pilot randomized controlled trials (RCTs) to acquire preliminary data regarding trial design. We propose a 3-Arm, 16-week, pilot RCT (n=120) for low-income adults (aged 18+) with T2DM (A1c >7% [53 mmol/mol]). The control group (n=40) will receive usual care (UC). The two intervention groups (n=40 each) will receive UC plus a F&V Rx that is either independent of DSME/S attendance (F&V Rx alone) or dependent on DSME/S attendance (F&V Rx + DSME/S). First, we will systematically explore the impact of a F&V Rx on uptake and retention in DSME/S. Next, we will explore changes in A1c, and diet-related outcomes. Finally, with implementation in mind, we will use Proctor’s implementation taxonomy, and the cultural adaptation framework from Castro et al., to assess program appropriateness, acceptability, and sustainability with both participants and clinical care providers. Our study team and our Community Advisory Board (CAB) have the research, clinical expertise, and established retail network necessary to conduct a F&V Rx trial in a low-income, Hispanic community. The findings of this trial will inform the design of a future, fully powered RCT and address gaps in our knowledge related to how F&V Rx programs impact T2DM-related outcomes. If effective, F&V Rx programs have the potential to improve diabetes self-management and reduce the clinical burden of poor glycemic control, particularly in low-income, Hispanic communities.