Aldosterone and refractory hypertension

Resistant hypertension (blood pressure 140/90 mmHg on 3 anthypertensive agents) is a common problem in clinical practice. Several factors induce treatment resistance, especially unrecognized secondary hypertension. Aldosterone/renin ratio (ARR) is an index for inappropriate aldosterone activity and it could be helpful to predict the response to anthypertensive agents. Aim of our study was evaluate inappropriate aldosterone activity in causing resistance to anthypertensive therapy. Among the patients from the Hypertension Outpatient Clinic that were consecutively evaluated for the first time between 1995 and 2001, we selected all the patients (n 157) with aldosterone-associated hypertension (AAH, ARR (ng dL / ng mL h) 25, plasma aldosterone 12 ng/dL). 58 were diagnosed as idiopathic hyperaldosteronism (IHA, aldosterone after captopril suppression test 15) and 91 as “high aldosterone hypertension” (HAH, aldosterone after captopril 15). Patients with Conn adenoma (n 8) were excluded from the study. As a control group, we randomly chose 160 patients with essential hypertension and plasma aldosterone 12 (EH). Anthypertensive treatment was given in accordance to WHO Guidelines (1999). The study end-point was blood pressure 140/90 mmHg. At baseline, there was no significant difference between the AAH and EH group with respect to age, BMI, systolic blood pressure, serum potassium, and creatinine. On the contrary, those with AAH had higher diastolic blood pressure (104 1 vs 98 1 mmHg, p 0.001), serum sodium (142.1 0.2 vs 141.4 0.2 mEq/L, p 0.05), and lower serum uric acid (4.09 0.03 vs 4.11 0.03 mg/dL, p 0.01) in comparison with EH group. During the follow-up (22 2 months), 59 (40%) patients with AAH and 72 (54%) patients in EH group reached the end point. According to survival analysis the patients with AAH reached the end-point in a smaller fraction and in a longer time compared with EH group, with no difference between IHA and HAH. At the end of followup, diastolic blood pressure was higher in AAH group compared with EH group. In IHA, spironolactone-based therapy was associated with a lower blood pressure at the end of follow-up in comparison with those without spironolactone. Inappropriate aldosterone activity in HAH is a risk factor for resistance to anthypertensive agents and the benefits of spironolactone is worth testing.