REVIEW QUESTION

Does reducing blood pressure to lower targets decrease the risk of morbidity and mortality in patients with hypertension and cardiovascular disease (CVD)?

TYPE OF REVIEW

A systematic review of six studies with a total of 9,484 participants.

RELEVANCE FOR NURSING

Hypertension is a known predictor of adverse patient outcomes, including increased morbidity and mortality. As the risks of uncontrolled hypertension have become better understood, the target goals for acceptable systolic and diastolic blood pressure have become lower. These lower goals have a direct impact on patient care, usually leading to intensification of pharmacologic treatment.

Although patients with hypertension and a history of CVD are considered at high risk for CVD events, the risks versus the benefits of tight blood pressure control in this population are not well understood. It is helpful for health care providers who care for patients with concomitant hypertension and CVD risk factors (such as a history of myocardial infarction, angina, stroke, or peripheral vascular disease) to know whether reaching lower blood pressure targets is associated with reductions in morbidity and mortality compared with attaining standard targets.

CHARACTERISTICS OF THE EVIDENCE

The objective of this systematic review was to establish whether the achievement of lower blood pressure targets (<=135/85 mmHg) compared with standard targets (<=140-160/90-100 mmHg) is associated with decreased risk of morbidity and mortality in adult patients with hypertension and preexisting CVD who were receiving pharmacotherapeutic treatment for hypertension.

Six studies were included, for a total of 9,484 participants. The primary outcomes were total mortality, total serious adverse events (SAE), total cardiovascular events, and cardiovascular mortality. Overall, there were no statistically significant differences in the four primary outcomes between the lower- and standard-target groups. As expected, fewer patients in the lower-target groups achieved their blood pressure goals after 12 months. Patients in the lower-target groups also did not have a reduced risk of total or cardiovascular mortality, and they had no additional cardiovascular benefits such as fewer total cardiovascular events or SAEs. There was very limited evidence on adverse effects. This suggests that no net benefit is derived from a lower blood pressure target.

Although the review authors stated that studies did not adequately report patient withdrawals as a result of adverse effects, data showed that more patients withdrew from the lower-target groups. The quality of the evidence was moderate for the mortality outcomes, low for SAE and total cardiovascular events, and very low for the safety outcomes (withdrawals).

BEST PRACTICE RECOMMENDATIONS

At present, evidence is insufficient to justify lower blood pressure targets in people with hypertension and established CVD. This review challenges the "lower is always better" theory for a range of important, patient-centered outcomes. Although there is an increasing interest in the potential benefits of lower blood pressure goals, this review indicates that there were no major advantages to patients regarding morbidity and mortality from tighter blood pressure control.

RESEARCH RECOMMENDATIONS

Well-designed, randomized controlled trials assessing lower blood pressure targets in patients with hypertension and established CVD are needed to ascertain the benefits and harms of intensive versus conservative strategies. Future research should aim to report mortality rates and all SAE outcomes.

REFERENCE