How Low To Go for Hypertension in the Elderly

Abstract & Commentary

By Mary Elina Ferris, MD, Clinical Associate Professor, University of Southern California. Dr. Ferris reports no financial relationship to this field of study.

Synopsis: Diastolic blood pressures as low as 55mm Hg in the elderly were not found to be harmful when treating systolic hypertension; however, for those with known coronary heart disease, a minimum value of 70mm Hg is advised.

Source: Fagard RH, et. al. Arch Intern Med. 2007;167(17):1884-1891.

Data from the Systolic Hypertension in Europe (Syst-Eur) Trial, a randomized, prospective placebo-controlled trial involving patients over age 59 in 198 centers, looked at 4,695 patients with systolic pressures between 160-219mm Hg and diastolic pressures under 95mm. Initial treatment consisted of a calcium channel blocker, with the addition of ACE-inhibitor and hydrochlorothiazide if needed. After an average period of 2 years, the control group was switched to active treatment along with the other treated group. Extended follow-up continued for 4 additional years. No increased cardiovascular mortality was observed with active hypertensive treatment that caused a diastolic pressure as low as 55mm Hg, if patients with baseline evidence of coronary heart disease were excluded. The placebo group which had lower diastolic blood pressures without treatment had a higher incidence of cerebrovascular events, but not cardiac events. The treated group with low diastolic pressures had no increased risk for cerebrovascular events. Increased mortality from cancer and noncardiovascular causes was associated with low diastolic pressures in both the treated and placebo groups.

Commentary

This study helps us determine how aggressively to treat systolic hypertension in the geriatric population. While we know that lowering systolic pressures is strongly recommended to prevent strokes and other cardiac events, this treatment may also result in a low diastolic pressure, which at a certain point becomes associated with a higher incidence of cardiovascular deaths (called the "J-curve"). Specifically, the Systolic Hypertension in the Elderly Program (SHEP) found that lowering the diastolic pressure to less than 70mm Hg caused more harm than benefit.1 That study used treatment with chlorthalidone, and addition of beta-blockers and reserpine if needed.

However, this new analysis of the Syst-Eur Trial was able to separate out a subset of elderly patients with known coronary heart disease who had more risk with a lower diastolic pressure; for others, there was no increased cardiovascular mortality for a value as low as 55mm Hg. Although the SHEP trial showed an increase in cardiovascular events starting at 70mm diastolic pressure, with a 2-fold increase at 55mm, this was not the case in this new study when the group had no known pre-existing disease. The authors note that all deaths in both the control and treated groups from non-cardiac causes increase at lower diastolic pressures, suggesting that the J-curve observations may actually be caused by ill health and not by the low diastolic pressure.

Thus the conclusion is reached that we should treat systolic hypertension more aggressively, even if it causes a diastolic pressure as low as 55mm Hg, unless the patient has a risk of death from either cardiac or other causes. However, since many of the elderly will fall in this high-risk category, the general standard will likely continue to be a minimum diastolic pressure of 70mm, with a smaller healthy group eligible to receive the benefits of more aggressive therapy, even if it causes a pressure as low as 55mm Hg.

Reference

1. Somes GW, et al. Arch Intern Med. 1999;159(17):2004-2009.