Initial combination therapy with irbesartan/hydrochlorothiazide for hypertension: an analysis of the relationship between baseline blood pressure and the need for combination therapy.

Hypertension treatment guidelines recommend initiating 2-drug therapy whenever blood pressure (BP) is > or =20 mm Hg systolic or > or =10 mm Hg diastolic above goal. This post hoc pooled analysis of 2 multicenter, randomized, double-blind, active-controlled forced-titration studies in 1235 patients with moderate and severe hypertension examined how baseline BP levels relate to the need for combination therapy by comparing the antihypertensive efficacy and tolerability of once-daily fixed-dose irbesartan/hydrochlorothiazide (HCTZ) 300/25 mg compared with irbesartan 300-mg or HCTZ 25-mg monotherapies. In study 1, patients with severe hypertension (seated diastolic BP [SeDBP] > or =110 mm Hg) were treated for 7 weeks with irbesartan or irbesartan/HCTZ combination therapy, with forced-titration after week 1. In study 2, patients with moderate hypertension (seated systolic BP [SeSBP] 160-180 mm Hg or SeDBP 100-110 mm Hg) were treated for 12 weeks with irbesartan/HCTZ, irbesartan monotherapy, or HCTZ monotherapy, with forced-titration after week 2. The relationship between baseline BP and the likelihood of achieving BP goals (SeSBP <140 mm Hg or SeDBP <90 mm Hg; SeSBP <130 mm Hg or SeDBP <80 mm Hg) as well as the antihypertensive response was evaluated at week 7/8. The need for combination therapy increased with increasing baseline BP and lower BP goals across the range of BP levels studied, with a comparable adverse effect profile to monotherapy. These results suggest that the likelihood of achieving an early BP goal for a given BP severity should be considered when choosing initial combination therapy vs monotherapy.