Background Hypertension is an important issue in Asia,responsible for up to 66％ of cardiovascular disease cases.This randomized controlled trial subgroup analysis compared telmisartan 80 mg (T80)/hydrochlorothiazide 25 mg (H25) singlepill combination with T80 monotherapy,specifically in Chinese and Korean patients.Methods Patients with grade 2/3 hypertension were randomized to receive telmisartan 40 mg (T40)/hydrochlorothiazide 12.5 mg (H12.5) combination or T40 monotherapy for one week,before uptitrating the dose to T80/H25 or T80,respectively,for the remaining 6 weeks.The primary endpoint was systolic blood pressure (SBP) mean change from baseline.Secondary endpoints included mean diastolic blood pressure (DBP) change from baseline,and blood pressure (BP) goal achievement.Adverse events were recorded.Results Of a total 888 patients who were treated,efficacy analyses for Chinese and Korean patients included 127 patients treated with T80/H25 and 54 patients treated with T80.At week 7,mean SBP reductions from baseline were -37.5 mmHg (1 mmHg=0.133 kPa) and-26.9 mmHg in the T80/H25 and T80 groups (adjusted mean difference,-10.6 mmHg; 95％ confidence interval (CO,-15.6 to-5.7).Mean DBP reductions were-19.0 and-14.1 mmHg in the T80/H25 and T80 groups (adjusted mean difference,-4.9 mmHg; 95％ CI,-8.0 to-1.8).In total,56.7％ of patients receiving T80/H25 achieved BP goal (＜140/90 mmHg) compared with 35.2％ receiving T80.SBP goal attainment (＜140 mmHg) and DBP goal attainment (＜90 mmHg) were also higher in the T80/H25 group compared with the T80 group (SBP:69.3％ vs.48.1％; DBP:62.2％ vs.46.3％).A small number of treatment-related adverse events were observed in both T80/H25 (nine patients,6.9％) and T80 monotherapy (two patients,3.6％) groups.Conclusions In Chinese and Korean patients with moderate-to-severe hypertension,treatment with T80/H25 provided large reductions in mean SBP and DBP,and high BP goal attainment rates.This once-daily combination is effective and well tolerated in this patient group.(ClinicalTrials.gov identifier NCT00926289)