Does intensive blood pressure lowering further reduce the risk of cardiovascular and renal complications?

This analysis examined the effect of reduced blood pressure on major cardiovascular events such as heart attacks and strokes. The incidence of these events was reviewed compared to the blood pressure values achieved with treatment. The effect of blood pressure reduction on kidney damage was also reviewed.

High blood pressure puts patients at an elevated risk for strokes, heart attacks, and kidney and eye damage. Current guidelines recommend blood pressure should be reduced to a systolic blood pressure (SBP) of less than 140 mmHg. SBP refers to the high value on a blood pressure measurement, while diastolic blood pressure refers to the low value. Whether or not a greater reduction in SBP would benefit patients with hypertension is currently under debate. It is generally believed that "lower is better", and that patients at high risk (such as patients with concurrent diseases like diabetes or coronary artery disease) should be treated more intensely. Some studies have shown that a greater reduction decreases the risk of cardiovascular events, while other studies have shown that a reduction that is too great might be harmful. The effect of greater than standard reduction in blood pressure on kidney damage has not yet been confirmed.

In this meta-analysis (a large analysis of data combined from several similar trials) 15 controlled clinical trials, including more than 35,000 patients with hypertension, were reviewed. The analysis included several studies with conservative blood pressure targets (SBP around 140mmHg), and several trials in which a more intense reduction was achieved (SBP<130mmHg, or SBP <120mmHg). Some of the trials referred to a reduction in diastolic blood pressure rather than SBP.

Data suggested that a more intensive blood pressure lowering was associated with a 13% reduction in the risk of heart attacks. A 24% reduction in the risk of strokes was also noted with more intensive therapy. However, no survival benefit was found when intensive therapy was compared to more conservative targets.  Intensive lowering also showed an 11% decrease in the risk for kidney failure. A 19% reduction in the risk of eye damage was also noted in patients with diabetes (although these findings showed a large degree of variability and should not be considered conclusive).

Management of blood pressure is important in the prevention of heart attacks, strokes and organ damage. A greater reduction in blood pressure was linked to a greater reduction in the risk of these events, but did not show a benefit on overall survival.

The trials reviewed in this analysis did not properly report on the harmful side effects of intensive blood pressure lowering. In addition, many of the trials included diabetic patients. The effect of therapy on non diabetic patients was not discussed separately.

Consult with your doctor regarding your individual target pressure and how to reach it.