Spironolactone reduces severity of obstructive sleep apnoea in patients with resistant hypertension: a preliminary report

Obstructive sleep apnoea (OSA) and hyperaldosteronism are very common in subjects with resistant hypertension. We hypothesized that aldosterone-mediated chronic fluid retention may influence OSA severity in patients with resistant hypertension. We tested this in an open-label evaluation by assessing the changes in the severity of OSA in patients with resistant hypertension after treatment with spironolactone. Subjects with resistant hypertension (clinical blood pressure (BP) ⩾140/90 mm Hg on ⩾3 antihypertensive medications, including a thiazide diuretic and OSA (defined as an apnoea–hypopnoea index (AHI) ⩾15) had full diagnostic, polysomnography before and 8 weeks after spironolactone (25–50 mg a day) was added to their ongoing antihypertensive therapy. In all, 12 patients (mean age 56 years and body mass index 36.8 kg m–2) were evaluated. After treatment with spironolactone, the AHI (39.8±19.5 vs 22.0±6.8 events/h; P<0.05) and hypoxic index (13.6±10.8 vs 6.7±6.6 events/h; P<0.05), weight and clinic and ambulatory BP were significantly reduced. Plasma renin activity (PRA) and serum creatinine were significantly higher. This study provides preliminary evidence that treatment with a mineralocorticoid receptor antagonist substantially reduces the severity of OSA. If confirmed in a randomized assessment, it will support aldosterone-mediated chronic fluid retention as an important mediator of OSA severity in patients with resistant hypertension.