Objective: To assess whether the relative and absolute benefit of hypertension treatment in women varies with age or race.
Design: Systematic review of studies from 1966 to 1998 using MEDLINE, reviews, and consultation with experts. Eleven randomized controlled trials of pharmacologic treatment of prJgiary hypertension with cardiovascular morbidity and mortality outcomes were selected, with a pooled population of 23,000 women. Relative risks were combined for each end point to form a summary risk ratio using meta-analytic techniques based on a random-effects model. Summary risk ratios were converted to numbers needed to treat (NNTs). Data were dichotomized by age to approxJgiate menopausal status (30 to 54 years, and 55 years and older), and by race (white and African American).
Main results: In women aged 55 years or older (90% white), hypertension treatment resulted in a 38% risk reduction in fatal and nonfatal cerebrovascular events (95% confidence interval [CI] 27%, 47%; 5-year NNT 78), a 25% reduction in fatal and nonfatal cardiovascular events (95% CI 17%, 33%; 5-year NNT 58), and a 17% reduction in cardiovascular mortality (95% CI 3%, 29%; 5-year NNT 282). In women aged 30 to 54 years (79% white), hypertension treatment resulted in a 41% risk reduction in fatal and nonfatal cerebrovascular events (95% CI 8%, 63%; 5-year NNT 264), and a 27% risk reduction in fatal and nonfatal cardiovascular events (95% CI 4%, 44%; 5-year NNT 259). Hypertension treatment in African-American women (mean age, 52 years) reduced the risk of fatal and nonfatal cerebrovascular events by 53% (95% CI 29%, 69%; 5-year NNT 39), fatal and nonfatal cardiovascular events by 45% (95% CI 18%, 63%; 5-year NNT 21), fatal and nonfatal coronary events by 33% (95% CI 6%, 52%; 5-year NNT 48), and all-cause mortality by 34% (95% CI 14%, 49%; 5-year NNT 32). Analyses in white women aged 30 to 54 years did not show any statistically significant treatment benefit or harm.
Conclusions: Hypertension treatment lowers the relative and absolute risk of cardiovascular morbidity and mortality in women aged 55 years and older and in African-American women of all ages. A greater effort should be made to increase awareness and treatment in these groups of women. Although relative risk reductions for cerebrovascular and cardiovascular events are sJgiilar for younger and older women, the NNT of younger women is at least 4 tJgies higher. Decisions about treatment of hypertension in younger white women should be influenced by the individual patient's absolute risk of cardiovascular disease.