Hyperkalemia commonly occurs among outpatients, and certain classes of antihypertensive medications are associated more strongly with the condition, a study found.
Monitoring and management of hyperkalemia in a real-world setting may differ from clinical trials. So investigators led by Alex R. Chang, MD, of Geisinger Health System in Danville, PA, studied the occurrence of hyperkalemia among 194,456 outpatients who attended the rural health system in 2011. The researchers defined hyperkalemia at 2 different cutpoints: potassium levels above 5 mEq/L and above 5.5 mEq/L.
Over 3 years, potassium levels higher than 5 mEq/L and 5.5 mEq/L occurred in 10.8% and 2.3% of patients, according to results published online ahead of print by Hypertension. Among patients who had their potassium levels measured frequently (4 or more times a year), 39.4% and 14.6% had hyperkalemia according to these definitions. These patients tended to be older males with hypertension, diabetes, atherosclerotic cardiovascular disease, congestive heart failure, estimate glomerular filtration rate below 60 mL/min/1.73m2, or proteinuria. Hyperkalemia occurred just once in most cases.
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After adjusting for comorbidities, use of angiotensin-converting enzyme inhibitors (ACEIs) was the strongest risk factor for hyperkalemia among antihypertensive medications. Clinicians discontinued or reduced the dosage of ACEIs and angiotensin receptor blockers (ARBs) in 49.6% of cases and potassium-sparing diuretics in 29.1%. Medication changes were more common in this study than reported in previous trials.
Renin-angiotensin-aldosterone system (RAAS) inhibitors can increase the risk of hyperkalemia, so the Kidney Disease Improving Global Outcomes (KDIGO) clinical practice guideline recommends monitoring serum potassium within a week of starting these medications. “Our findings suggest potential hyperkalemia management strategies could include switching RAAS inhibitor class from ACEIs to ARBs or prescribing or adjusting the dose of thiazide/loop diuretics,” according to Dr Chang and colleagues.
There’s also opportunity for greater nephrology involvement. Among patients with potassium levels above 5.5 mEq/L, only 24% saw a nephrologist and 5.3% visited a dietitian within 3 years. “Despite KDIGO recommendations, patterns of hyperkalemia did not correlate with seeing a nephrologist, and relatively few patients with even persistent hyperkalemia were seen by a dietitian in our cohort,” Dr Chang and colleagues stated.
When patients presented with high potassium levels, 3.1% went to the emergency room within 7 days; 44.3% had their potassium levels re-measured within 2 weeks, and 26.4% had a change in potassium-altering medication.
More research is needed to determine whether dietary strategies, kaliuretic diuretics, or potassium binders can improve outcomes. As this study including mostly white patients from a single healthcare system, the results may not pertain to all patients.
