Association of Serum Potassium with All-Cause Mortality in Patients with and without Heart Failure, Chronic Kidney Disease, and/or Diabetes

TLDR

The link between serum potassium levels, mortality, and common dyskalemia‑associated conditions such as heart failure, chronic kidney disease, and diabetes is largely unknown. Using electronic medical record data from 911,698 patients, the authors applied cubic spline regression to evaluate how index potassium values predict 18‑month all‑cause mortality across the overall population, a control group, and subgroups with heart failure, chronic kidney disease, diabetes, and a combined cohort. They found a U‑shaped relationship, with lowest mortality for potassium 4.0–<5.0 mEq/L, and progressively higher mortality with hypo‑ or hyperkalemia—especially in heart failure (22 %), chronic kidney disease (16.6 %), and diabetes (6.6 %)—and noted that each 0.1 mEq/L shift below 4.0 or above 5.0 increased risk, with older age and certain medications further elevating mortality.

Abstract

&lt;b&gt;&lt;i&gt;Background: &lt;/i&gt;&lt;/b&gt;The relationship between serum potassium, mortality, and conditions commonly associated with dyskalemias, such as heart failure (HF), chronic kidney disease (CKD), and/or diabetes mellitus (DM) is largely unknown. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; We reviewed electronic medical record data from a geographically diverse population (&lt;i&gt;n&lt;/i&gt; = 911,698) receiving medical care, determined the distribution of serum potassium, and the relationship between an index potassium value and mortality over an 18-month period in those with and without HF, CKD, and/or DM. We examined the association between all-cause mortality and potassium using a cubic spline regression analysis in the total population, a control group, and in HF, CKD, DM, and a combined cohort. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; 27.6% had a potassium &lt;4.0 mEq/L, and 5.7% had a value ≥5.0 mEq/L. A U-shaped association was noted between serum potassium and mortality in all groups, with lowest all-cause mortality in controls with potassium values between 4.0 and &lt;5.0 mEq/L. All-cause mortality rates per index potassium between 2.5 and 8.0 mEq/L were consistently greater with HF 22%, CKD 16.6%, and DM 6.6% vs. controls 1.2%, and highest in the combined cohort 29.7%. Higher mortality rates were noted in those aged ≥65 vs. 50-64 years. In an adjusted model, all-cause mortality was significantly elevated for every 0.1 mEq/L change in potassium &lt;4.0 mEq/L and ≥5.0 mEq/L. Diuretics and renin-angiotensin-aldosterone system inhibitors were related to hypokalemia and hyperkalemia respectively. &lt;b&gt;&lt;i&gt;Conclusion:&lt;/i&gt;&lt;/b&gt; Mortality risk progressively increased with dyskalemia and was differentially greater in those with HF, CKD, or DM.