When treating elevated blood pressure, healthcare practitioners need to know what blood pressure target they should try to achieve.
The attempt to achieve lower blood pressure targets has been the emphasis of major guidelines published in recent years.1-6 The standard target pressure has generally been the arbitrary threshold blood pressure above which treatment is recommended. The standard target systolic blood pressure declined from a target of ≤160 mmHg to a target ≤140mm Hg and the diastolic blood pressure target has decreased from ≤100mmHg to ≤90mmHg in the recent guidelines. The Joint National Committee (JNC) on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommendations were published in 2003 and JNC VIII is anticipated later this year. This trend assumes that treating to lower blood pressure targets with antihypertensive medications will achieve a reduction in cardiovascular morbidity and mortality similar to that seen in earlier epidemiological observational studies, where a direct relationship between adverse cardiovascular events and increasing levels of blood pressure was observed.7
Nevertheless, the attempt to achieve lower blood pressure targets has several consequences; the most obvious is the need for increased number of antihypertensive drugs in larger doses, that could lead to increased adverse drug effects and subsequently worse cardiovascular outcomes.8,9
A Cochrane meta-analysis of randomized controlled trials was recently conducted to address this issue.10 The objectives of this study were to determine if there is a reduction in total mortality and morbidity associated with treatment of blood pressure to “lower targets of ≤135/85 mmHg” as compared with “standard targets of 140-160/90-100 mmHg,” to determine if there is a change in mean achieved systolic and diastolic blood pressure associated with “lower targets” and to determine if there is a change in withdrawals due to adverse events with “lower targets” as compared with “standard targets” in patients with elevated blood pressure.
This systematic review summarized the available evidence that has tested blood pressure targets and included 22,089 patients, with a mean follow-up period of 3.8 years. The search strategy included an electronic search of MEDLINE (1966-2008), EMBASE (1980-2008), and CENTRAL (up to June 2008); references from review articles, clinical guidelines, and clinical trials. Randomized controlled trials comparing patients randomized to “lower targets” or to “standard targets” and providing data on any of the primary outcomes below were included. Participants were adults with elevated blood pressure documented on at least 2 occasions or those already on antihypertensive drugs. Primary outcomes were total mortality; total serious adverse events; total cardiovascular events; myocardial infarction, stroke, congestive heart failure, and end stage renal disease. Secondary outcomes were achieved mean systolic and diastolic BP and withdrawals due to adverse effects.
No trials comparing different systolic BP targets were found. Twenty four references appeared appropriate for the systematic review, seven (22,089 subjects) from 18 publications were randomized controlled trials comparing different diastolic blood pressure targets were included.
Studies included were the Modification of Diet in Renal Disease (MDRD) trial, the Hypertension Optimal Treatment (HOT) trial, and ...