Plant-Focused Nutrition in Patients with Diabetes and Chronic Kidney Disease (PLAFOND Study): A Pilot/Feasibility Study - SUMMARY Chronic kidney disease (CKD) affects 10-15% of US adults including 30-40% of persons with diabetes mellitus (DM), is associated with poor outcomes, and often progresses to requiring dialysis or transplantation. Half of all Americans with CKD also have DM. While traditional and emerging pharmacotherapies are often used in CKD with diabetes (CKD/DM), the synergistic role of dietary interventions has not been well examined. Low-carbohydrate low-fat diets are often recommended in DM, whereas low-protein diets (LPDs) are recommended for non-diabetic CKD with increasing emphasis on plant-based protein sources. Evidence suggests that high-protein diets with greater animal protein content may lead to glomerular hyperfiltration and faster decline in renal function in patients with CKD/DM. There remains major controversy regarding the potential risks vs. benefits of plant-based diets in CKD/DM, for which guidelines remain based on expert opinion. Given conventional dietary restrictions for the management of DM, there is concern that plant-based LPDs may lead to protein-energy wasting and hyperkalemia, whereas these diets may indeed be most beneficial in patients with CKD/DM given their faster rates of CKD progression as compared to non-diabetics. At present, clinical practice guidelines provide conflicting recommendations regarding the amount (low vs. high) and source (plant vs. animal) of dietary protein intake (DPI) in CKD/DM. Given that prior dietary trials in CKD such as the 1994 Modification of Diet in Renal Disease (MDRD) study excluded CKD/DM and did not examine the optimal proportion of plant vs. animal-based proteins, there is urgent unmet need for a rigorous dietary intervention study to examine the efficacy and safety of patient-centered plant-based diets in CKD/DM. In the spirit of PAS 20-160 (Small R01s for Clinical Trials Targeting NIDDK Diseases) we propose a pilot feasibility randomized controlled trial, conducted in parallel with patients' routine follow-up visits at two CKD clinics within the University of California Irvine, to test the feasibility and safety of implementing a Plant- Focused Nutrition in CKD/DM (PLAFOND) diet with a DPI of 0.6-0.8 g/kg/d comprised of >2/3 plant-based sources, vs. standard-of-care renal diet with <1/3 plant-sources and low-potassium content, administrated by dietitians, over a 6-month period in 120 patients with CKD/DM stage 3-5. We will determine whether the PLAFOND diet vs. the standard-of-care renal diet can be adhered to with consistent separation in dietary protein and plant-based proportions at 3- and 6-months. We will also examine nutritional status, physical performance, and body composition, as well as glycemic measures using traditional metrics and continuous glucose monitoring, while other biochemical parameters and patient-reported outcomes including CKD-related symptoms will also be studied. In addition to providing the requisite feasibility and safety data of patient- centered dietary regimens needed for the design and conduct of future multi-center trials, our proposed study will have major immediate impact by reinvigorating the critical role of dietary management of CKD/DM.
