Clinical trial NCT01897727
Conditions: Obstructive Sleep Apnea Resistant Hypertension Hyperaldosteronism
Keywords: sleep apnea hypertension aldosterone hyperaldosteronism spironolactone blood pressure resistant
Sponsor: University of Alabama at Birmingham
Start date: 2009-01-01; Completion date: 2012-04-01
Enrollment: 41 participants; Allocation: RANDOMIZED; Intervention model: PARALLEL

Brief summary:
Hypertension affects an estimated 60-70 million Americans, predisposing them to potentially life threatening cardiovascular complications. Resistant hypertension, defined as uncontrolled blood pressure on 3 or more different antihypertensive agents, is common, affecting 15-20% of the entire hypertensive population or an estimated 12-14 million Americans. Although associated with obesity, increasing age, black race, and chronic kidney disease, mechanisms of treatment resistance remain obscure. The investigators' laboratory identified primary aldosteronism (PA) as a common cause of treatment resistance with a prevalence of 20% among subjects with resistant hypertension. This is clinically important because recognition of PA can lead to effective treatment with use of aldosterone blockers. Obstructive sleep apnea (OSA) is strongly associated with and predicts development of hypertension as demonstrated in landmark cohort studies including the Sleep Heart Health Study and the Wisconsin Sleep Cohort Study.

The investigators' laboratory has confirmed OSA to be extremely common in subjects with resistant hypertension, with a prevalence of approximately 85%. Recognizing that PA and OSA are exceptionally common in subjects with resistant hypertension, the investigators hypothesized that the 2 may be causally related. In testing this hypothesis, the investigators recently reported that plasma aldosterone levels are positively correlated with OSA severity in subjects with resistant hypertension but not in normotensive control subjects. This observation suggests that there is an important mechanistic interaction between untreated OSA and aldosterone excess in subjects with resistant hypertension. While the investigators' original hypothesis was that OSA stimulates aldosterone release, the investigators recognize that the opposite may also be true; that is, aldosterone excess in subjects with resistant hypertension worsens OSA. Distinguishing between these two possibilities has potentially far-reaching clinical implications. If the former hypothesis is true, effective treatment of OSA would be expected to suppress aldosterone release in subjects with resistant hypertension, thereby reversing the underlying cause of their treatment resistance. If the latter hypothesis is true, use of mineralocorticoid receptor antagonists would be expected to reduce OSA severity in subjects with resistant hypertension, thereby enhancing treatment of OSA. Either scenario would represent a new treatment approach for a highly prevalent and serious medical problem.

Detailed description:

Arms: arm 1: Spironolactone 25 mg administered following baseline measurements and uptitrated to 50 mg if BP \> 140/90 mm Hg throughout the 3 month study. arm 2: Antihypertensive medication added and/or uptitrated to keep BP \< 140/90 mm Hg throughout the study.
Interventions: intervention 1: Spironolactone intervention 2: BP medication uptitration
Intervention descriptions: intervention 1: None intervention 2: antihypertensive medication added or uptitrated following standard of care

Protocol documents: