Association of low diastolic blood pressure with all-cause death among US adults with normal systolic blood pressure

Although the effect of intensive systolic blood pressure lowering is widely recognized, treatment-related low diastolic blood pressure still worrisome. This was a prospective cohort study based on the National Health and Nutrition Examination Survey. Adults (>= 20 years old) with guideline-recommended blood pressure were included and pregnant women were excluded. Survey-weighted logistic regression and cox models were used for analysis. A total of 25 858 participants were included in this study. After weighted, the overall mean age of the participants was 43.17 (16.03) years, including 53.7% women and 68.1% non-Hispanic white. Numerous factors were associated with low DBP (<60 mmHg), including advanced age, heart failure, myocardial infarction, and diabetes. The use of antihypertensive drugs was also associated with lower DBP (OR, 1.52; 95% CI, 1.26-1.83). DBP of less than 60 mmHg were associated with a higher risk of all-cause death (HR, 1.30; 95% CI, 1.12-1.51) and cardiovascular death (HR, 1.34; 95% CI, 1.00-1.79) compared to those with DBP between 70 and 80 mmHg. After regrouping, DBP <60 mmHg (no antihypertensive drugs) was associated with a higher risk of all-cause death (HR, 1.46; 95% CI, 1.21-1.75). DBP <60 mmHg after taking antihypertensive drugs was not associated with a higher risk of all-cause death (HR, 0.99; 95% CI, 0.73-1.36). Antihypertensive drug is an important factor contributing to DBP below 60 mmHg. But the pre-existing risk does not increase further with an additional reduction of DBP after antihypertensive drugs treatment.