Patients with stage 3b-4 chronic kidney disease (CKD) who take a potassium chloride (KCl) supplement to meet dietary potassium recommendations run the risk of hyperkalemia, a new study finds. Salt substitutes commonly contain potassium chloride.

Research has suggested that adequate dietary potassium intake (90-120 mmol/d) may be renoprotective.

Investigators treated 191 patients with CKD (mean age 68 years; 74% male; 86% White) with 40 mmol KCl per day for 2 weeks. The amount of KCl was equivalent to eating 4 bananas daily.

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KCl supplementation significantly increased urinary potassium excretion (72 to 107 mmol/d), plasma potassium (4.3 to 4.7 mmol/L), and plasma aldosterone (281 to 351 ng/L), but it did not significantly improve urinary sodium excretion, plasma renin, blood pressure, estimated glomerular filtration rate (eGFR), or albuminuria, Ewout J. Hoorn, MD, PhD, of Erasmus Medical Center, Rotterdam, The Netherlands, and colleagues reported in the Journal of the American Society of Nephrology. KCl supplementation also significantly increased plasma chloride (104 to 105 mmol/L), decreased plasma bicarbonate (24.5 to 23.7 mmol/L), and decreased urine pH. Yet it did not change urinary ammonium excretion. “KCl supplementation caused a clear tendency towards hyperchloremic metabolic acidosis,” according to the investigators.

Hyperkalemia developed in 21 (11%) of the 191 patients. Mean plasma potassium increased from 4.9 to 5.9 mmol/L.

On multivariable analysis, each 10-year increment in age and each 0.5 mmol/L increment in plasma potassium at baseline was significantly associated with 2.2- and 24.2-fold increased odds of hyperkalemia after KCl supplementation for 2 weeks, respectively, Dr Hoorn’s team reported. Patients who experienced hyperkalemia had significantly less urinary potassium excretion compared with those with normokalemia (24 vs 36 mmol/d). Most patients were also taking renin-angiotensin inhibitors.

“Our results suggest that changes in plasma potassium with KCl supplementation are mostly driven by factors regulating tubular potassium secretion and acid-base balance,” Dr Hoorn’s team stated. “The identification of these factors may help to individualize potassium supplementation in patients with CKD.”

As the study continues, the investigators will test potassium citrate and placebo to determine whether the benefits of increasing dietary potassium intake outweigh the risks of hyperkalemia.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Gritter M, Wouda R, Yeung S, et al. Effects of short-term potassium chloride supplementation in patients with chronic kidney disease. J Am Soc Nephrol. Published online May 24, 2022. doi:10.1681/ASN.2022020147