Kidney Week

Abstract: FR-PO1064

Effects of a Low-Protein Diet in Patients with CKD Taking Renin-Angiotensin System Inhibitors: A Post Hoc Subanalysis of the RICE Study

Session Information

• Kidney Nutrition and Metabolism
  October 25, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Health Maintenance, Nutrition, and Metabolism

• 1500 Health Maintenance, Nutrition, and Metabolism

Authors

• Hosojima, Michihiro, Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan

Michihiro Hosojima, MD, PhD

• Kabasawa, Hideyuki, Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan

Hideyuki Kabasawa, MD, PhD

• Tanaka, Mai, Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan

Mai Tanaka, MS

• Saito, Akihiko, Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan

Akihiko Saito, MD, PhD

• Narita, Ichiei, Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan

Ichiei Narita, MD, PhD

Background

Globally, evidence for dietary therapy in patients with chronic kidney disease (CKD) is lacking, and there is an urgent need to accrue such evidence. Previously, we conducted the "Randomized Crossover Trial of Therapeutic Specialized Foods (Low-Protein Rice) for Patients with Chronic Kidney Disease (RICE Study) (Clinical Trial registration number: UMIN000015630)" and demonstrated that the use of low-protein rice (LPR) improves adherence to recommended protein-restricted diets and leads to a reduction in urinary protein in CKD patients. However, some opinions suggest that most reports supporting a low-protein diet (LPD) were conducted before the widespread use of renin-angiotensin system (RAS) inhibitors. Hence, it is crucial to investigate the impact of LPDs on CKD patients who are on RAS inhibitors.

Methods

The RICE study included 104 patients with CKD (Stages G3aA2 to G4) who were randomly assigned to receive nutritional counseling every four weeks alone (control group) or in addition to LPR (LPR group) for 24 weeks. The primary outcome was estimated dietary protein intake determined using the Maroni formula. The secondary outcomes included creatinine clearance (CCr) and urinary protein on the basis of 24-hour urine collection. In this sub-analysis, we targeted only patients taking RAS inhibitors (42 in each group) and conducted similar evaluations.

Results

Protein intake decreased from 1.00 g to 0.90 g/kg ideal body weight (IBW)/day in the control group and from 1.01 g to 0.77 g/kg IBW/day in the LPR group. Adjusted protein intake at baseline showed a decrease of 0.14 g/kg IBW/day (95% CI, 0.0003 to 0.27 g/kg IBW/day) in the LPR group compared to the control group at 24 weeks (P = 0.049). Similarly, urinary protein levels decreased significantly by 0.45 g/day (95% CI, 0.15 to 0.74 g/day) in the LPR group compared to the control group at 24 weeks (P = 0.003). There was no significant difference in CCr between the two groups at 24 weeks.

Conclusion

The LPD using LPR is effective in achieving protein restriction and may contribute to the reduction of urinary protein levels, even in patients with CKD taking RAS inhibitors. Further detailed verification, including prospective studies, is required in the future.