Liberal fruit and vegetable intake in patients with advanced CKD with or without Sodium zirconium cyclosilicate

Higher dietary potassium intake is associated with lower blood pressure, better kidney outcomes and improved survival. However, the risk of hyperkalemia limits implementation of healthy potassium-rich diets in patients with chronic kidney disease(CKD). Novel potassium binders such as sodium zirconium cyclosilicate(SZC) may enable a more liberal intake of potassium-rich diets and thereby enable their cardiorenal benefits.

This randomized, crossover, non-inferiority clinical trial included 16 CKD patients receiving RAAS inhibitors. Participants followed, in a randomized order, a potassium-rich diet for 6 weeks (adding 40mmol potassium/day via extra fruits, vegetables and nuts) or their regular diet. Hyperkalemia (>5.5mmol/l) was managed with SZC, while continuing the diet. The primary endpoint was serum potassium after 6 weeks, with a non-inferiority margin of 0.5mmol/l.

At 6 weeks, there was no significant difference in serum potassium between the control and potassium-enriched diet phases (between-group difference 0.03mmol/L, 95%CI-0.32to0.27;p=0.850). In contrast,24-hour urinary potassium excretion increased significantly during the potassium-enriched diet (between-group difference 24.7mmol/24h, 95%CI8.0to 41.3; p=0.005). Two patients developed hyperkalemia (5.9 and 6.1 mmol/L) and were treated with SZC, after which the diet was continued without recurrence.

A potassium-rich diet was consistent with non-inferior serum potassium levels compared with a regular diet at 6 weeks in patients with advanced CKD receiving RAAS inhibition. Hyperkalemia occurred in a minority of patients, and was effectively managed with SZC, allowing continuation of both the diet and RAAS inhibition. These findings suggest that a potassium-rich diet may be feasible in selected patients with advanced CKD, with careful monitoring and use of SZC when needed.