Selection of initial antihypertensive therapy, regimen design, and goal blood pressure.

Systolic and diastolic blood pressures (BPs) have a strong, continuous, graded, and etiologically significant positive association with cardiovascular disease outcomes. Small reductions in systolic and diastolic BP lead to large and proportionate reductions in ischemic heart disease, stroke, and vascular mortality. A recently reported meta-analysis of nearly a million people without pre-existing vascular disease and participating in clinical trials or observational studies analyzed the relationship between BP and cardiovascular mortality (1). A steep, direct log-linear relationship between systolic and diastolic BP was seen with mortality caused by stroke, ischemic heart disease, and other vascular diseases, including heart failure. The dose-response relationship is seen continuously until 89 years of age. Thus, even the very old have the same relationship between BP and vascular mortality. The million people meta-analysis also was unable to find a threshold at which BP reduction does not yield benefit. The lowest usual BP at any age associated with the best outcomes was 115/75 mmHg. The proportionality of risk reduction also reveals that 20 mmHg systolic BP reduction from 130 to 110 mmHg translates to the same risk reduction as from 180 to 160 mmHg. Vasan et al. (2) analyzed the relationship of high-normal BP with cardiovascular outcomes in men and women in the Framingham cohort. Four BP categories— optimal, normal, high-normal, and hypertension—were studied as defined by the Sixth Joint National Committee. High-normal BP was associated with increased cardiovascular events in both men and women. Even after adjusting for other cardiovascular risk factors (age, body mass index, total cholesterol, diabetes, smoking, and examination year), the risk of first major cardiovascular event was increased 40% in women and 20% in men per change in BP category. A continuous trend for cardiovascular disease across the 3 nonhypertensive BP categories was seen. The authors conclude, “A 20% overall absolute risk of CV events at 10 years currently defines the threshold for treatment of hypertension. In subjects 65 years age, the 10-year absolute risk exceeded 20% in men and approached this in women. Assuming a 25% risk reduction, the estimated number needed to treat over 5 years would be 28 men or 41 women.” These data show that no BP reduction is trivial, and the risk reduction is log-linear. Thus, if the baseline absolute risk is high, the reduction in BP needed to reduce cardiovascular outcomes will be evident with a smaller number of patients.