Dietary potassium intake linked with blood potassium concentration in patients with CKD: study

Observational studies suggest that adequate dietary potassium intake (90–120 mmol/day) may be renoprotective, but the effects of increasing dietary potassium and the risk of hyperkalemia are unknown.

This is a prespecified analysis of the run-in phase of a clinical trial in which 191 patients (age 68±11 years, 74% males, 86% European ancestry, eGFR 31±9 ml/min per 1.73 m2, 83% renin-angiotensin system inhibitors, 38% diabetes) were treated with 40 mmol potassium chloride (KCl) per day for 2 weeks.

Results:

• KCl supplementation significantly increased urinary potassium excretion, plasma potassium, and plasma aldosterone, but had no significant effect on urinary sodium excretion, plasma renin, BP, eGFR, or albuminuria.
• Furthermore, KCl supplementation increased plasma chloride and reduced plasma bicarbonate and urine pH, but did not change urinary ammonium excretion.
• In total, 21 participants (11%) developed hyperkalemia
• They were older and had higher baseline plasma potassium.

The researchers concluded that in patients with CKD stage G3b–4, increasing dietary potassium intake to recommended levels with potassium chloride supplementation raises plasma potassium by 0.4 mmol/L. This may result in hyperkalemia in older patients or those with higher baseline plasma potassium. Longer-term studies should address whether cardiorenal protection outweighs the risk of hyperkalemia.

In the study Higher baseline plasma potassium and older age were risk factors for developing hyperkalemia after supplementation. Potassium chloride supplementation did not lower office BP, but did cause a tendency toward hyperchloremic metabolic acidosis. Longer-term studies should determine whether the cardiorenal benefits of adequate dietary potassium intake outweigh the risk of hyperkalemia in patients with CKD.

Reference:

Martin Gritter, et al. Effects of Short-Term Potassium Chloride Supplementation in Patients with CKD. JASN September 2022, 33 (9) 1779-1789; DOI: https://doi.org/10.1681/ASN.2022020147