Low Diastolic Blood Pressure and Mortality in Older Women. Results From the Women's Health Initiative Long Life Study

Background: Recommended systolic blood pressure targets often do not consider the relationship of low diastolic blood pressure (DBP) levels with cardiovascular disease (CVD) and all-cause mortality risk, which is especially relevant for older people with concurrent comorbidities. We examined the relationship of DBP levels to CVD and all-cause mortality in older women in the Women's Health Initiative Long Life Study (WHI-LLS). Methods: The study sample included 7,875 women (mean age: 79 years) who underwent a blood pressure measurement at an in-person home visit conducted in 2012-2013. CVD and all-cause mortality were centrally adjudicated. Hazard ratios (HRs) were obtained from adjusted Cox proportional hazards models. Results: After 5 years follow-up, all-cause mortality occurred in 18.4% of women. Compared with a DBP of 80 mm Hg, the fully adjusted HR for mortality was 1.33 (95% confidence interval [CI]: 1.04-1.71) for a DBP of 50 mm Hg and 1.67 (95% CI: 1.29-2.16) for a DBP of 100 mm Hg. The HRs for CVD were 1.14 (95% CI: 0.78-1.67) for a DBP of 50 mm Hg and HR 1.50 (95% CI: 1.03-2.17) for a DBP of 100 mm Hg. The nadir DBP associated with lowest mortality risk was 72 mm Hg overall. Conclusions: In older women, consideration should be given to the potential adverse effects of low and high DBP. Low DBP may serve as a risk marker. DBP target levels between 68 and 75 mm Hg may avoid higher mortality risk.