Masked uncontrolled
hypertension (MUCH) in treated patients is defined as controlled office blood pressure (BP) but uncontrolled out-of-clinic ambulatory BP. Previously, we have shown that patients with MUCH have evidence of heightened out-of-clinic sympathetic nervous system activity. The aim is to test the hypothesis that MUCH patients have higher
aldosterone secretion compared with patients with true controlled
hypertension. Two hundred twenty-two patients were recruited after having controlled office BP readings at ≥3
clinic visits. Patients taking MR (
mineralocorticoid receptor) antagonists and
epithelial sodium channel blockers were excluded. All patients were evaluated by clinic automated office BP and morning serum
aldosterone and plasma
renin activity. Out-of-clinic ambulatory BP monitoring and 24-hour urinary
aldosterone,
catecholamines, and metanephrines were also measured. Sixty-four patients had MUCH, and the remaining 48 patients had true controlled
hypertension. MUCH patients had significantly higher out-of-clinic levels of 24-hour urinary
aldosterone,
catecholamines, and metanephrines compared with true controlled
hypertension. The 2 groups did not differ in serum
aldosterone, plasma
renin activity, or
aldosterone-
renin ratio collected in clinic. In addition, 32.8% of MUCH patients had high out-of-clinic 24-hour urinary
aldosterone (≥12 µg) but normal clinic serum
aldosterone (<15 ng/dL) and
aldosterone-
renin ratio (<20). Further, in correlation matrix analysis, higher 24-hour urinary
catecholamines and metanephrines were associated with higher 24-hour urinary
aldosterone and plasma
renin activity levels in MUCH patients. Patients with MUCH have higher out-of-clinic urinary
aldosterone levels compared with patients with true controlled
hypertension. This study suggests that patients with MUCH likely have higher out-of-clinic sympathetic nervous system tone increases
aldosterone secretion mediated by increased
renin release that may contribute to their higher out-of-clinic BP.