Plant-based diet in hyperkalemic chronic kidney disease patients receiving sodium zirconium cyclosilicate: a feasibility clinical trial

Abstract

Background: Plant-based diets (PBD) may induce hyperkalemia in chronic kidney disease (CKD) patients.

Objectives: We explored the safety and feasibility of PBD in hyperkalemic CKD patients receiving the potassium binder sodium zirconium cyclosilicate (SZC).

Methods: In the current 6-wk trial, 26 hyperkalemic patients with CKD stage 4-5 not on dialysis received a low-protein low-potassium diet plus SZC for 3 wk and then a PBD with high potassium content delivered as a weekly food basket while continuing SZC for subsequent 3 wk. Plasma potassium was monitored weekly and SZC was titrated to achieve normokalemia. The 24-h urine excretion of potassium and sodium, 24-h food records, dietary quality, nutritional status, Bristol stool scale, Quality of life (QoL), and renal treatment satisfaction were assessed at baseline (week 0), week 3, and week 6.

Results: Mean plasma potassium decreased from 5.5 to 4.4 mEq/L within 48-72 h after baseline, then rose to 4.7-5.0 mEq/L throughout the remaining study period following dose adjustments of SZC that matched the increased potassium intake of PBD from week 3 to week 6. Over the study period, 24-h urinary potassium excretion decreased from week 0 to week 3 and increased from week 3 to week 6. During the study, 58% of patients had fasting plasma potassium between 3.5 and 5.0 mEq/L and there was no episode of plasma potassium >6.5 mEq/L or <3.0 mEq/L during the study. P-carbon dioxide increased from baseline until week 6 (21 ± 2 to 23 ± 2 mEq/L; P = 0.002; mean ± SD), whereas remaining laboratory values remained unchanged. Fiber intake, dietary quality, the domain physical functioning from QoL, and 1 question of renal treatment satisfaction improved, whereas stool type and frequency did not change after starting PBD.

Conclusions: PBD in hyperkalemia-prone CKD patients receiving SZC improved dietary quality and increased the intake of healthy foods, whereas plasma potassium concentration remained stable within normal values for most patients.

Trial registration number: This trial was registered at the https://clinicaltrials.gov/study/NCT04207203 as NCT04207203.

Keywords: chronic kidney disease; dietary potassium; hyperkalemia; plant-based diet; potassium binders.

FIGURE 1

Study design and procedures (n = 26). CRP, C-reactive protein; HbA1c, glycated hemoglobin; PB, plant-based; PK, plasma potassium; QoL, Quality of Life; SZC, sodium zirconium cyclosilicate.

FIGURE 2

Potassium control during the study (n = 26). (A) Fasting plasma potassium (n = 26); repeated measure ANOVA test (P < 0.01). Post hoc analysis with Bonferroni correction for multiple comparisons: ∗Indicates P < 0.05 for the comparison between week 0 to all other time points. ∗∗Indicates P < 0.05 between week 0_48–72 h and all time points. ∗∗∗Indicates P < 0.05 between week 3 and week 3_48 h. (B) Number of patients with hyperkalemia (plasma potassium: 5.1 to <6.5 mEq/L) (n = 26). (C) Potassium intake assessed by 24-h food record (n = 26). Repeated measure ANOVA test (P < 0.01). Post hoc analysis with Bonferroni correction for multiple comparisons: ∗Indicate P < 0.05 for the comparison between week 5 to all other time points. ∗∗Indicate P < 0.05 between week 6 and all time points. (D) SZC prescribed daily dose (n = 26). ANOVA, analysis of variance; SZC, sodium zirconium cyclosilicate.