Hyperkalemia and Hypokalemia in CKD: Prevalence, Risk Factors, and Clinical Outcomes

Abnormalities of serum potassium are common in patients with CKD. Although hyperkalemia is a well-recognized complication of CKD, the prevalence rates of hyperkalemia (14%-20%) and hypokalemia (12%-18%) are similar. CKD severity, use of medications such as renin-angiotensin-aldosterone system inhibitors and diuretics, and dietary potassium intake are major determinants of serum potassium concentration in CKD. Demographic factors, acid-base status, blood glucose, and other comorbidities contribute as well. Both hyperkalemia and hypokalemia are associated with similarly increased risks of death, cardiovascular disease, and hospitalization. On the other hand, limited evidence suggests a link between hypokalemia, but not hyperkalemia, and progression of CKD. This article reviews the prevalence rates and risk factors for hyperkalemia and hypokalemia, and their associations with adverse outcomes in CKD. Abnormalities of serum potassium are common in patients with CKD. Although hyperkalemia is a well-recognized complication of CKD, the prevalence rates of hyperkalemia (14%-20%) and hypokalemia (12%-18%) are similar. CKD severity, use of medications such as renin-angiotensin-aldosterone system inhibitors and diuretics, and dietary potassium intake are major determinants of serum potassium concentration in CKD. Demographic factors, acid-base status, blood glucose, and other comorbidities contribute as well. Both hyperkalemia and hypokalemia are associated with similarly increased risks of death, cardiovascular disease, and hospitalization. On the other hand, limited evidence suggests a link between hypokalemia, but not hyperkalemia, and progression of CKD. This article reviews the prevalence rates and risk factors for hyperkalemia and hypokalemia, and their associations with adverse outcomes in CKD. Clinical Summary•The prevalence of hyperkalemia and hypokalemia in CKD are similar, although severe hyperkalemia (≥5.5 mEq/L) is more common than severe hypokalemia (<3.5 mEq/L).•Kidney function, medications, demographic factors, acid-base status, and other factors are key determinants of serum potassium concentration.•The association between serum potassium and mortality and cardiovascular events is u-shaped.•Potassium concentrations in the 4-5 mEq/L range are associated with the lowest risk of adverse outcomes. •The prevalence of hyperkalemia and hypokalemia in CKD are similar, although severe hyperkalemia (≥5.5 mEq/L) is more common than severe hypokalemia (<3.5 mEq/L).•Kidney function, medications, demographic factors, acid-base status, and other factors are key determinants of serum potassium concentration.•The association between serum potassium and mortality and cardiovascular events is u-shaped.•Potassium concentrations in the 4-5 mEq/L range are associated with the lowest risk of adverse outcomes.