Am Fam Physician. 2010;81(7):848-850
Author disclosure: Nothing to disclose.
A 52-year-old man who is otherwise healthy has been diagnosed with hypertension. He and his physician decide to start medication therapy, and they discuss what target blood pressure he should aim to achieve.
When treating uncomplicated hypertension, is there a benefit to choosing a lower target blood pressure of less than or equal to 135/85 mm Hg, rather than the standard blood pressure goal of less than or equal to 140 to 160/90 to 100 mm Hg?
To date, there is no evidence to support treating patients with uncomplicated hypertension to blood pressure goals lower than the standard blood pressure target of less than or equal to 140 to 160/90 to 100 mm Hg. In randomized controlled trials, patients treated to lower blood pressure targets did not have better survival, less heart or kidney failure, or fewer cardiovascular events or strokes compared with those treated to the standard blood pressure target.1 (Strength of Recommendation = A, based on consistent and good-quality patient-oriented evidence)
Although hypertension in the United States has been traditionally defined as blood pressure greater than or equal to 140/90 mm Hg, prospective epidemiologic studies have demonstrated a continuous and primarily linear relationship between blood pressure and adverse health outcomes. As blood pressure rises, so does the risk of cardiovascular disease, renal failure, stroke, and death.2–5 There is good evidence that lowering systolic blood pressure by 12 mm Hg over 10 years reduces the risk of cardiovascular events, cardiovascular death, and death from any cause.6 However, healthy patients had a considerably smaller risk reduction than patients with at least one other major cardiovascular risk factor or patients with preexisting cardiovascular disease or target organ damage.6 Patients who had a higher baseline blood pressure (greater than or equal to 160/100 mm Hg) also had greater benefit from treatment than those with more moderate hypertension (140 to 159/90 to 99 mm Hg) or prehypertension (130 to 139/85 to 89 mm Hg).6
Based on existing epidemiologic evidence, many recent hypertension treatment guidelines—including those of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure7 and the American Heart Association8—have recommended blood pressure treatment targets of less than or equal to 130/80 mm Hg in high-risk patients, such as those with diabetes mellitus, renal disease, coronary artery disease, or its risk equivalents. However, it is unclear whether achieving a lower blood pressure goal provides additional benefit to patients with uncomplicated hypertension.
The Cochrane review of this topic examined randomized controlled trials that compared patients treated to the standard blood pressure goal of less than or equal to 140 to 160/90 to 100 mm Hg with those treated to a lower goal of less than or equal to 135/85 mm Hg.1 The Cochrane reviewers only considered trials that had data on the primary outcomes of total mortality, total serious adverse events, total cardiovascular events, myocardial infarction, stroke, congestive heart failure, or end-stage renal disease. Although trials comparing different systolic blood pressure goals were not identified, seven trials comparing different diastolic blood pressure goals yielding data from more than 22,000 adults met these criteria. Data from these trials showed that patients treated to a lower diastolic blood pressure goal also achieved lower systolic blood pressures.
Background: When treating elevated blood pressure, physicians need to know what blood pressure target they should try to achieve. The standard of clinical practice for some time has been less than or equal to 140 to 160/90 to 100 mm Hg. New guidelines are recommending blood pressure targets lower than this standard. It is not known whether attempting to achieve targets lower than the standard reduces mortality and morbidity.
Objectives: To determine if lower blood pressure targets (less than or equal to 135/85 mm Hg) are associated with reduction in mortality and morbidity compared with standard blood pressure targets (less than or equal to 140 to 160/90 to 100 mm Hg).
Search Strategy: Electronic search of Medline (1966 to 2008), EMBASE (1980 to 2008), and CENTRAL (up to June 2008); references from review articles, clinical guidelines, and clinical trials.
Selection Criteria: Randomized controlled trials comparing patients randomized to lower or to standard blood pressure targets and providing data on any of the primary outcomes below.
Data Collection and Analysis: Two reviewers independently assessed the included trials and data entry. Primary outcomes were total mortality; total serious adverse events; total cardiovascular events; and myocardial infarction, stroke, congestive heart failure, and end-stage renal disease. Secondary outcomes were achieved mean systolic and diastolic blood pressure and withdrawals because of adverse effects.
Main Results: No trials comparing different systolic blood pressure targets were found. Seven trials (n = 22,089) comparing different diastolic blood pressure targets were included. Despite a −4/−3 mm Hg greater achieved reduction in systolic/diastolic blood pressure (P ≤ .001), attempting to achieve “lower targets” instead of “standard targets” did not change total mortality (risk ratio [RR] = 0.92; 95% confidence interval [CI], 0.86 to 1.15), myocardial infarction (RR = 0.90; 95% CI, 0.74 to 1.09), stroke (RR = 0.99; 95% CI, 0.79 to 1.25), congestive heart failure (RR = 0.88; 95% CI, 0.59 to 1.32), major cardiovascular events (RR = 0.94; 95% CI, 0.83 to 1.07), or end-stage renal disease (RR = 1.01; 95% CI, 0.81 to 1.27). The net health effect of lower targets cannot be fully assessed because of a lack of information about all total serious adverse events and withdrawals because of adverse effects in six of the seven trials. A sensitivity analysis in patients with diabetes mellitus and in patients with chronic renal disease also did not show a reduction in any of the mortality and morbidity outcomes with lower targets as compared with standard targets.
Authors' Conclusions: Treating patients to lower than standard blood pressure targets does not reduce mortality or morbidity. Because guidelines are recommending even lower targets for diabetes and chronic renal disease, we are currently conducting systematic reviews in those groups of patients.
These summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (http://www.cochrane.org).
An analysis of data from these trials showed that the risks of overall mortality, myocardial infarction, congestive heart failure, major cardiovascular events, stroke, and end-stage renal disease did not differ significantly between patients treated to the lower blood pressure goal and those treated to the standard goal. Patients treated to the lower blood pressure target, on average, took more antihypertensive medications and at higher doses, but there was insufficient evidence to determine if these patients had more medication-related adverse events or withdrawals from treatment. Regardless, the finding of lack of benefit was robust. A sensitivity analysis lowering the target blood pressure to less than or equal to 130/80 mm Hg did not change the results.1 Therefore, the blood pressure treatment goal for patients with uncomplicated hypertension should remain at less than or equal to 140 to 160/90 to 100 mm Hg. This is consistent with the current National Heart, Lung and Blood Institute guidelines, which recommend a target of less than or equal to 140/90 mm Hg for the average-risk patient.8
One important limitation that should be emphasized is that current guidelines for hypertension treatment recommend lower blood pressure treatment targets specifically for high-risk patients, rather than for all patients with hypertension.1,7,8 Nonetheless, the focus of this Cochrane review was to examine blood pressure treatment targets for the general population.1 Although the Cochrane reviewers did not find a significant benefit of lower blood pressure goals for the subset of patients with diabetes or chronic renal disease, this finding was relatively imprecise and no conclusive recommendation could be made for these higher-risk patients from this review.1