Efficacy of Add-On Aldosterone Receptor Blocker in Uncontrolled Hypertension

BACKGROUND: Uncontrolled hypertension (UH) may be caused by hyperaldosteronism, and some experts recommend the routine use of aldosterone antagonists in this condition. The purpose of this study was to evaluate the efficacy of this approach and to characterize those who respond effectively to an add-on aldosterone antagonist. METHODS: We retrospectively analyzed the effectiveness of spironolactone, an aldosterone antagonist, used as add-on therapy, compared with a standard add-on treatment, in patients referred to a hypertension clinic with UH despite the use of two or more antihypertensive drugs. RESULTS: A total of 340 patients (186 male) with an average age of 63 +/- 14 years were followed for at least 3 months. Of the patients, 42 received add-on spironolactone and 298 received an additional antihypertensive drug other than spironolactone. Baseline characteristics were similar in both groups. Blood pressure (BP) decreased significantly in both groups. In patients who received spironolactone, BP decreased by 23.2/12.5 mm Hg from 165 +/- 27/94 +/- 15 to 142 +/- 25/81 +/- 9 mm Hg, whereas in patients who received other add-on therapy BP decreased by 7.6/5.8 mm Hg from 160 +/- 24/91 +/- 12 to 152 +/- 20/85 +/- 11 mm Hg (P < .05). Patients who received spironolactone had lower serum potassium levels than those who did not receive spironolactone 3.8 +/- 0.4 v 4.5 +/- 0.5 mmol/L respectively (P < .001). Potassium levels <4 mmol/L were associated with a greater reduction in BP. CONCLUSIONS: Add-on spironolactone is a highly effective add-on treatment in UH, mainly in patients with low serum potassium levels. Further studies assessing serum potassium as a marker for treatment approach are needed to establish the role of aldosterone antagonists in the management of UH.