• Myth No. 5: No hypokalemia means no primary hyperaldosteronism. Resistant hypertension (defined as above-goal blood pressure despite the use of at least three optimally dosed medications from different classes) is present in 35% of hypertensive patients. Primary hyperaldosteronism is the cause of resistant hypertension in 10%-20% cases. In the past, the diagnosis of primary hypoaldosteronism leaned heavily on the presence of hypokalemia. More recently, however, studies demonstrate that normokalemic hypertension is the most common presentation of primary hyperaldosteronism; hypokalemia is present in only 9%-37% of cases, and these tend to be the most severe ones.
Screening for primary hyperaldosteronism is warranted in all patients with resistant hypertension with no other explanation, in those with an abnormal-appearing adrenal gland on CT, and in those with hypokalemia. The combination of a plasma aldosterone–to– plasma renin activity ratio greater than 30, plus an absolute plasma aldosterone concentration above 20 ng/dL, has been shown to have 90% sensitivity and 91% specificity for primary aldosteronism, Dr. Mehler continued.
Most affected patients respond to spironolactone with a marked blood pressure reduction. This drug, which costs pennies per day, is one of just four cardiovascular medications that were developed before 1960 and are still widely used today. The others are digoxin, aspirin, and warfarin, he noted.
Dr. Mehler reported having no financial conflicts.