Background—Diuretics are recommended as first-line agents for the treatment of hypertension. This randomized, double-blind, multicenter study assessed the long-term efficacy and safety of the direct renin inhibitor aliskiren in comparison with the diuretic hydrochlorothiazide in patients with essential hypertension.

Methods and Results—After a 2- to 4-week placebo run-in, 1124 patients (mean sitting diastolic blood pressure [BP] 95 to 109 mm Hg) were randomized to aliskiren 150 mg (n=459), hydrochlorothiazide 12.5 mg (n=444), or placebo (n=221) once daily. Forced titration (to aliskiren 300 mg or hydrochlorothiazide 25 mg) occurred at week 3; at week 6, patients receiving placebo were reassigned (1:1 ratio) to aliskiren 300 mg or hydrochlorothiazide 25 mg. From week 12, amlodipine 5 mg was added and titrated to 10 mg from week 18 for patients whose BP remained uncontrolled. Efficacy variables were analyzed for the intent-to-treat population with the use of the last observation carried forward method. BP reductions (mean sitting systolic BP/mean sitting diastolic BP) were significantly greater with aliskiren- versus hydrochlorothiazide-based treatment at week 26 (-20.3/-14.2 versus -18.6/-13.0 mm Hg; P<0.05) and were also greater at week 52 (-22.1/-16.0 versus -21.2/-15.0 mm Hg; P<0.05 for mean sitting diastolic BP). At the end of the monotherapy period (week 12), aliskiren 300 mg was superior to hydrochlorothiazide 25 mg in reducing BP (-17.4/-12.2 versus -14.7/-10.3 mm H; P<0.001). Adverse event rates were similar with aliskiren- (65.2%) and hydrochlorothiazide-based therapy (61.5%). Hypokalemia was more frequent with hydrochlorothiazide-based therapy than aliskiren-based therapy (17.9% versus 0.9%; P<0.0001).

Conclusions—Aliskiren treatment, both as monotherapy and with optional addition of amlodipine, provided significantly greater BP reductions than the respective hydrochlorothiazide regimens. Aliskiren-based therapy was well tolerated. Direct renin inhibition with aliskiren therefore represents an effective option for the long-term treatment of essential hypertension.