An ambulatory blood pressure monitoring study of the comparative antihypertensive efficacy of two angiotensin II receptor antagonists, irbesartan and valsartan.

BACKGROUND

The primary objective of this study was to compare the change from baseline in mean diastolic ambulatory blood pressure (ABP) at 24 h post dose (trough measurement) after 8 weeks of treatment with irbesartan or valsartan in subjects with mild-to-moderate hypertension. Secondary objectives included comparing the mean changes from baseline in systolic ABP at trough; 24-h ABP; morning and night-time ABP; self-measured systolic blood pressure (SBP) and diastolic blood pressure (DBP); and office-measured SBP and DBP at trough.

DESIGN

After a 3-week, single blind, placebo lead-in period, 426 subjects were randomized to receive either irbesartan 150 mg or valsartan 80 mg for 8 weeks.

METHODS

Ambulatory blood pressure measurements were obtained at baseline and at week 8. Self-measured morning and evening DBP and SBP readings were obtained at home over a 7-day period at baseline and at week 8. Office-measured seated DBP and SBP measurements were obtained at trough, at baseline, and at week 8.

RESULTS

Irbesartan demonstrated significantly greater reductions than valsartan for mean change from baseline in diastolic ABP at trough (-6.73 versus -4.84 mmHg, respectively; P = 0.035). Irbesartan produced significantly greater reductions than valsartan for mean systolic ABP at trough (-11.62 versus -7.5 mmHg, respectively; P < 0.01) and for mean 24-h diastolic ABP (-6.38 versus -4.82 mmHg, respectively; P = 0.023) and systolic ABP (-10.24 versus -7.76 mmHg; P < 0.01). Irbesartan also produced significantly greater reductions than valsartan for office-measured seated DBP (-10.46 versus 7.28 mmHg, respectively; P < 0.01) and SBP (-16.23 versus -9.96 mmHg, respectively; P < 0.01) and for self-measured morning DBP (-6.28 versus -3.75 mmHg, respectively; P < 0.01) and SBP (-10.21 versus -6.97 mmHg, respectively; P < 0.01). Both drugs were well tolerated.

CONCLUSION

Irbesartan was more effective than valsartan in reducing DBP and SBP at trough and in providing greater overall 24-h blood pressure-lowering efficacy.