A comparison of indapamide SR 1.5 mg with both amlodipine 5 mg and hydrochlorothiazide 25 mg in elderly hypertensive patients: a randomized double-blind controlled study

OBJECTIVE: To analyse the efficacy of indapamide sustained-release (SR) 1.5 mg in reducing blood pressure versus amlodipine 5 mg and hydrochlorothiazide 25 mg, in elderly hypertensive patients. DESIGN: Double-blind, randomized, 12 week study using three parallel groups. SETTING: European teaching hospitals and general practices. PATIENTS: Randomized patients, (n = 524) including 128 patients with isolated systolic hypertension (ISH); mean age: 72.4 years; mean systolic/diastolic blood pressures (SBP/DBP): 174.5/97.9 mmHg. MAIN OUTCOME MEASURES: Clinic systolic and diastolic blood pressure variations. RESULTS: Indapamide SR 1.5 mg demonstrates a similar efficacy to that of amlodipine 5 mg, as well as to that of hydrochlorothiazide 25 mg (equivalence P < 0.001); the mean decreases in SBP/DBP were -22.7/-11.8 mmHg, -22.2/-10.7 mmHg and -19.4/-10.8 mmHg, respectively. In the ISH subgroup, indapamide SR 1.5 mg tends to have greater efficacy than hydrochlorothiazide 25 mg in reducing the SBP (-24.7 versus -18.5 mmHg, respectively; equivalence P = 0.117), while similar results are obtained with amlodipine 5 mg (-23 mmHg, equivalence P < 0.001). The normalization rate was relatively high for indapamide SR 1.5 mg (75.3%), when compared with amlodipine (66.9%) and hydrochlorothiazide (67.3%), especially in the subgroup of isolated systolic hypertensive patients: 84.2 versus 80.0% for amlodipine, and versus 71.4% for hydrochlorothiazide. CONCLUSIONS: Indapamide SR 1.5 mg shows similar antihypertensive efficacy to amlodipine 5 mg and hydrochlorothiazide 25 mg in elderly hypertensive patients, while in patients with isolated systolic hypertension, indapamide SR 1.5 mg shows a similar efficacy to amlodipine 5 mg but a greater efficacy than hydrochlorothiazide 25 mg.