How does Chronic Kidney Disease (CKD) affect electrolyte levels?

From the Guidelines

Chronic Kidney Disease (CKD) significantly disrupts electrolyte balance in the body, leading to several imbalances, including hyperkalemia, hypocalcemia, and hyperphosphatemia, which can cause dangerous heart rhythm abnormalities and increase mortality risk. As kidney function declines, the kidneys lose their ability to properly filter and regulate electrolytes. Potassium levels often increase, which can cause heart rhythm abnormalities, while phosphorus retention occurs due to the kidneys' inability to excrete excess amounts, leading to an association with excess mortality at levels above and below the limits of normal 1. Calcium levels typically decrease due to reduced vitamin D activation and phosphorus retention. Sodium balance may be affected, with some patients retaining sodium and water, causing edema and hypertension, while others experience sodium wasting. Magnesium may accumulate as filtration decreases. Acid-base balance is also disrupted, commonly resulting in metabolic acidosis as the kidneys cannot effectively excrete acid.

These electrolyte disturbances worsen as CKD progresses through stages 1-5, with more severe imbalances in advanced disease. The body attempts to compensate through various mechanisms, but these eventually become insufficient as kidney function deteriorates. Management typically involves dietary restrictions, medications like phosphate binders, potassium-binding resins, and sodium bicarbonate, and ultimately dialysis in end-stage kidney disease to artificially regulate these electrolytes. Monitoring of electrolytes, especially phosphate, potassium, and magnesium, is crucial in hospitalized patients with CKD, as electrolyte disorders are common and can improve with treatment 1.

Key considerations in managing electrolyte imbalances in CKD include:

• Limiting potassium intake to prevent hyperkalemia, especially in patients with advanced CKD or those at risk of hyperkalemia 1
• Avoiding hypercalcemia, as higher calcium concentrations are associated with increased mortality in adults with CKD 1
• Monitoring and managing phosphorus levels, as phosphate retention is a common complication of CKD and is associated with excess mortality 1
• Considering the potential harm associated with a positive calcium balance, especially in patients with CKD stage G5D 1

Overall, the management of electrolyte imbalances in CKD requires a comprehensive approach that takes into account the patient's individual needs and the stage of their disease. By prioritizing the management of electrolyte imbalances, healthcare providers can help reduce the risk of complications and improve outcomes for patients with CKD.

From the FDA Drug Label

The efficacy of Veltassa was demonstrated in a two-part, single-blind randomized withdrawal study that evaluated Veltassa in hyperkalemic patients with CKD on stable doses of at least one renin-angiotensin-aldosterone system inhibitor (i.e., angiotensin-converting enzyme inhibitor, angiotensin II receptor blocker, or aldosterone antagonist).

CKD can affect electrolyte levels by causing hyperkalemia, which is an elevated level of potassium in the blood. The study shows that patients with CKD had a mean serum potassium level of 5.58 mEq/L, which is higher than the normal range.

• Key findings:
  • CKD can lead to hyperkalemia due to the kidney's reduced ability to filter and remove excess potassium from the blood.
  • Veltassa, a potassium-binding medication, was effective in lowering serum potassium levels in patients with CKD and hyperkalemia 2.
  • The treatment effect on serum potassium was maintained during continued therapy with Veltassa. The FDA drug label does not provide a comprehensive description of how CKD affects all electrolyte levels, only potassium.

From the Research

Effect of CKD on Electrolyte Levels

CKD can significantly affect electrolyte levels in the body, leading to various disorders. Some of the key effects include:

• Hyperkalemia: CKD can cause an increase in potassium levels in the blood, which can be life-threatening 3, 4.
• Electrolyte imbalances: CKD can disrupt the balance of electrolytes such as sodium, potassium, and calcium, leading to various complications 5, 6.
• Acid-base disorders: CKD can also lead to acid-base disorders, including metabolic acidosis and alkalosis, which can have serious consequences 5, 7.

Factors Contributing to Electrolyte Imbalances in CKD

Several factors can contribute to electrolyte imbalances in CKD, including:

• Decline in glomerular filtration rate (GFR): As GFR declines, the kidneys' ability to regulate electrolyte levels is impaired 3, 4.
• Medications: Certain medications, such as renin-angiotensin-aldosterone system (RAAS) inhibitors, can increase the risk of hyperkalemia in CKD patients 3, 4.
• Dietary factors: A high-potassium diet can exacerbate hyperkalemia in CKD patients 4.

Management of Electrolyte Disorders in CKD

Management of electrolyte disorders in CKD typically involves a combination of dietary changes, medications, and other interventions. Some of the key strategies include:

• Potassium binders: Medications such as patiromer and sodium zirconium cyclosilicate can help reduce serum potassium levels in CKD patients 3, 4.
• Dietary restrictions: Limiting potassium intake can help manage hyperkalemia in CKD patients 4.
• RAAS inhibitor therapy: Optimizing RAAS inhibitor therapy can help minimize the risk of hyperkalemia and other electrolyte disorders in CKD patients 3, 4.