Little is known about the frequency and patterns of
hyperkalemia in clinical settings. We evaluated the association between baseline
antihypertensive medications that may affect
potassium levels (
angiotensin-converting enzyme inhibitors,
angiotensin receptor blockers, β-blockers, loop/
thiazide diuretics, and
potassium-sparing diuretics) and
hyperkalemia, defined by
potassium >5 mEq/L and >5.5 mEq/L, over a 3-year time period in 194 456 outpatients in the Geisinger Health System, as well as actions taken after an episode of
hyperkalemia. The proportions of patients with 0, <2, 2 to 4, and ≥4
potassium measurements per year were 20%, 58%, 16%, and 6%.
Potassium levels >5 mEq/L and >5.5 mEq/L occurred in 10.8% and 2.3% of all patients over the 3-year period; among patients with ≥4 measurements per year, corresponding values were 39.4% and 14.6%. Most cases of
hyperkalemia occurred only once during follow-up. The
antihypertensive medication class most strongly associated with
hyperkalemia was
angiotensin-converting enzyme inhibitors. Among patients with a measurement of
potassium >5.5 mEq/L, only 24% were seen by a nephrologist and 5.2% were seen by a dietician during the 3-year period. Short-term actions after a
potassium measurement >5.5 mEq/L included emergency room visit (3.1% within 7 days), remeasurement of
potassium (44.3% with 14 days), and change in a
potassium-altering medication (26.4% within 60 days). The most common medication changes were discontinuation/
dose reduction of an
angiotensin-converting enzyme inhibitor/
angiotensin receptor blocker or
potassium-sparing
diuretic, which occurred in 29.1% and 49.6% of people taking these medications, respectively. In conclusion,
hyperkalemia is common. Future research may enable optimal renin-angiotensin-aldosterone system inhibitor use with improved management of
hyperkalemia.