THE CHRONIC RISK OF HYPERKALEMIA

What is chronic hyperkalemia?

Chronic hyperkalemia or frequent hyperkalemic events are caused by functional impairment of K+ excretion due to disease (most commonly seen in patients with CKD and/or heart failure) and the use of certain medications to treat underlying disease. This results in recurring episodes of >1 event per year and requires ongoing management.1-3

Several factors can increase the chronic risk of hyperkalemia

Several factors increase the likelihood of chronic hyperkalemia. These include progressive kidney decline, comorbidities, the use of medications that affect the RAAS, and a diet high in K+.1-6

Comorbidities

The majority of patients at high risk for chronic hyperkalemia will have some level of underlying kidney impairment. They will probably be our patients with CKD who have a history of hypertension, type 2 diabetes mellitus, and/or heart failure.3,7

Progressive Kidney Decline

And over time, their kidney function will inevitably continue to decline.3 As this happens, the GFR and the ability of the kidneys to effectively filter K+ decrease. The body will attempt to compensate for this by excreting excess K+ via the colon.8 However, the adaptive response will eventually hit a ceiling, giving rise to elevated serum K+ levels. (See more on the colon’s compensatory functions)

Medication

To further complicate the picture of hyperkalemia in patients with CKD and/or heart failure, several medications commonly used to treat these conditions are known to elevate serum K+. In addition to RAASi, other agents either taken by the patient or prescribed by the physician, such as NSAIDs (including COX-2 inhibitors), digoxin, and K-sparing diuretics, can potentiate the risk of hyperkalemia.3,6 (See more on how medications can increase the risk of hyperkalemia)

While some of these medications have significant benefits on kidney and cardiac outcomes, they have been shown to increase the level of serum potassium and, hence, the risk of hyperkalemia. This is especially true for patients with an eGFR <60 mL/min.6,9

Ultimately, the risk factors in patients with CKD and heart failure are multifactorial: disease progression, comorbidities, medications, and dietary factors all increase the risk of chronic hyperkalemia.10