Sex differences in response to angiotensin II receptor blocker-based therapy in elderly, high-risk, hypertensive Japanese patients: a subanalysis of the OSCAR study

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The OlmeSartan Calcium Antagonists Randomized (OSCAR) study is a multicenter, prospective, randomized, open-label, blinded, end point study of elderly hypertensive Japanese patients that compared the efficacy of a high-dose angiotensin II receptor blocker (ARB) treatment to an ARB plus calcium channel blocker (CCB) combination. In this pre-specified subgroup analysis, we compared the response to such therapy according to sex. A total of 1164 patients (515 (44%) men and 649 (56%) women) were included, and each gender was split into two nearly equal treatment groups. The primary end point was a composite of cardiovascular events and non-cardiovascular death. The baseline characteristics between the two treatment groups in each sex were similar, except for some variables. Male patients had lower systolic and higher diastolic blood pressure than female patients (156.8/85.7 vs. 158.5/84.2 mm Hg). At the end of the study, the mean systolic pressure was higher in the ARB group (134.4 mm Hg) than in the ARB plus CCB group (131.5 mm Hg; P=0.03) for men but not for women (135.4 vs. 133.4 mm Hg; P=0.12). For men, the primary outcome events tended to be higher in the ARB group than in the ARB plus CCB group (hazard ratio (HR)=1.66; P=0.055) but not for women (HR=0.97; P=0.92). This difference in men was due to cardiovascular events (HR=1.86; P=0.03). The interaction between sex and treatment group was not significant (P=0.17). These findings suggest that, in addition to blood pressure control, appropriate patient risk assessment is important for the treatment of hypertension, especially in male patients, as opposed to possible sex differences in treatment effects.