An update: women, hypertension and therapeutic efficacy

One in five Canadians has high blood pressure. The prevalence is as high as 58% in women between the ages of 65 and 74 years. Approximately 40% of stroke cases, 39% of myocardial infarction cases and 28% of end stage renal diseases are attributable to hypertension. Despite the burden that hypertension places on women, the effect of antihypertensive therapy on cardiovascular complications has not been well established. To address this knowledge gap, two meta-analyses with sex-specific results, including the most current randomized, controlled trials to evaluate hypertension treatment, were reviewed. The Individual Data Analysis of Antihypertensive (INDANA) intervention trials group and Quan and colleagues analyzed treatment benefits in 23,000 women and 19,975 men according to subgroup meta-analyses from 12 randomized, controlled trials that compared antihypertensive drug therapy with placebo. The meta-analyses demonstrated a statistically significant treatment benefit for all of the reported clinical outcomes in men of all ages and in black women. In women over the age of 54 years, antihypertensive treatment was associated with a significant reduction of fatal and nonfatal stroke, cardiovascular events and cardiovascular mortality. Overall, there was no significant difference in the relative treatment benefit in women and men; however, the absolute treatment benefit was lower in women than in men. Thus, the number needed to treat for the end points of fatal stroke, nonfatal stroke and cardiovascular events was one- to threefold higher for women than for men. Furthermore, white women between the ages of 30 and 54 years showed no treatment benefit or harm. Data from the 6.7-year follow-up in the Hypertension Detection and Follow-up Program (HDFP) trial suggested that this group of younger women might benefit from a longer duration of treatment. Indications for pharmacological intervention seem quite clear for all subgroups, excluding these younger women. Until further evidence is available for this low risk subgroup, the current recommendations for lifestyle modification cannot be challenged.