Endocrine Abstracts

Background: Data on the prevalence of primary aldosteronism (PA) in subjects with resistant hypertension (inadequate pressure control with three full-dose drugs, including a diuretic) are scanty and it is not known if PA is associated with a more severe vascular damage.

Aim: To determine the prevalence of PA in patients with resistant hypertension and define the possible association with early cardiovascular damage.

Methods: Seventy two patients with resistant hypertension consecutively recruited from patients referring to a tertiary care center for hypertension.

Results: Diagnosis of PA (aldosterone (pg/ml)/PRA(ng/ml/h) > 400 AND aldosterone >200 basally AND > 100 after NaCl test, after stopping both interfering drugs and low salt diet), was made in 20 subjects (27.8%); the remaining 52 were considered affected by Essential Hypertension (EH, 72.2%). By CT and adrenal venous sampling 4 patients (20%) were diagnosed to have an aldosterone-producing adenoma and underwent surgical treatment. PA and EH did not differ for age, BMI, smoking habit, glycemia, LDL cholesterol, HDL cholesterol and triglyceride levels, renal function, duration of hypertension and family history of hypertension, or diabetes mellitus, or early cardiovascular disease. Blood systolic pressure levels did not differ in the two groups, but diastolic was significantly higher in PA (104.5±10.9 vs 96.6±13.6 mmHg, P<0.02). Potassium was significantly lower in PA (3.5±0.5 vs 4.1±0.5 mEq/l, P<0.01).

In PA the rate of intima-media thickness > 0.9 mm was higher (41.2 vs 26.7%), though not significantly but microalbuminuria was significantly more frequent (52.6 vs 26.7%, P<0.05). Moreover, PA predicted significantly microalbuminuria (OR =6.54, CI 1.02–19.35, P<0.05) in a logistic regression model with glycemia, creatinine, IMT, family history of early cardiovascular disease.

Conclusions: PA is very frequent in hypertensive subjects resistant to pharmacological therapy. Patients with PA show early renal vascular damage more frequently than resistant hypertensive patients with normal mineralcorticoid function.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.