Screening for primary aldosteronism in hypertensive patients

The incidence of primary aldosteronism (PA) in hypertensive patients is much greater than previously thought and may be the most common form of secondary hypertension. Screening for PA with the plasma aldosterone (PAC; in ng/ml) to plasma renin activity (PRA; in ng/ml per hour) has led to an increase in the rate of diagnosis. A positive screen for PA is a PAC/PRA of > 30. Estimates of the incidence of PA among patients with essential hypertension range from 5–15%. To determine occurrence of PA in a hypertension referral clinic, we searched electronic medical records for subjects seen from May ’96 to May ’98 who a positive PAC/PRA and the preliminary diagnosis of PA. Subjects were screened if they had resistant hypertension or hypokalemia. All subjects with a positive ratio were treated with a potassium sparing diuretic. Blood pressure evaluation prior to and following initiation of this treatment is reported. One hundred and four patients with a mean age of 51 years had a positive screen. Sixty-six percent of the subjects were black; 61% male. (See Table) Mean Mean Potassium 3.7 mEq/L Pre SBP/DBP 166/100 mm/Hg Creatinine 1.03 mEq/L MAP* 122 Aldosterone 18.8 ng/ml Post SBP/DBP 141/89 mm/Hg Renin 0.3 ng/ml/hr MAP 115 PAC/PRA 70.9 *mean arterial blood pressure In conclusion, PA is common among hypertensive patients. Early detection of PA with a PAC/PRA may lead to early diagnosis, treatment and control in previously undetected secondary hypertension. Patients with resistant hypertension or hypokalemia should be evaluated for PA.