Dietary potassium intake linked with blood potassium concentration in patients with CKD
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Among patients with advanced chronic kidney disease, increasing dietary potassium consumption to recommended levels can increase blood potassium concentration on a short-term basis, according to results of this study.
Further, investigators found this could lead to hyperkalemia in older patients or individuals with higher baseline plasma potassium.
“Hyperkalemia (high blood potassium concentration) is a potentially dangerous complication of CKD. To prevent this, nephrologists and renal dietitians often recommend a low potassium diet. However, observational data suggest that a low potassium diet is detrimental for kidney health. This raises the question whether the indication for a low potassium diet (preventing hyperkalemia) outweighs the unfavorable effects of a low potassium diet. In addition, the relationship between dietary potassium intake and the blood potassium concentration in patients with CKD is incompletely understood,” Ewout J. Hoorn, MD, PhD, a professor of nephrology at the Erasmus Medical Center in The Netherlands, told Healio. “Our study took these questions as starting point and aimed to delineate the response to short-term (2 week) potassium supplementation in patients with CKD. The dose of potassium [40 mmol per day] was chosen such that it would increase dietary potassium intake from low to adequate (recommended intake).”
Study
Hoorn and colleagues conducted the prespecified analysis of the run-in phase of a clinical trial with 191 patients with advanced CKD and administered two capsules of potassium chloride (KCI) supplementation three times per day during meals, with a daily dose of 40 mmol potassium and 40 mmol chloride. Patients continued their regular diet, then returned for a follow-up after 2 weeks.
Using multivariable linear regression analyses, researchers detected baseline characteristics related to the change in plasma potassium after KCI supplementation. Additionally, researchers conducted logistic regression to determine which characteristics independently correlated with the development of hyperkalemia.
Results, future research
Analyses revealed KCI supplementation increased urinary potassium excretion, plasma potassium, plasma aldosterone and plasma chloride. While it reduced plasma bicarbonate and urine pH, the supplementation had no impact on urinary sodium excretion, plasma renin, blood pressure, eGFR or albuminuria. A total of 21 patients developed hyperkalemia, all of which were older and had higher baseline plasma potassium.
“Our data show that, in patients with CKD, there is a relationship between dietary potassium intake and the blood potassium concentration which, on average, increased by 0.4 mmol/L,” Hoorn told Healio. “Despite this rise, only a minority of the patients (11%) developed hyperkalemia. This is remarkable as the patients had advanced CKD and the majority used renin-angiotensin inhibitors, commonly used renoprotective drugs, which often contribute to hyperkalemia.”
“The next relevant question is what the long-term effects of potassium supplementation are on kidney function, blood pressure and cardiovascular complications. This will be addressed by our ongoing double-blind randomized clinical trial in which we treat patients with CKD with placebo, potassium chloride or potassium citrate supplementation for 2 years,” Hoorn said. “These results are expected in the coming years. If the trial shows positive results, the implication would be to recommend adequate dietary potassium intake in patients with CKD, which can be achieved by consuming potassium-rich foods, such as fruits and vegetables, nuts and dairy foods.”
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