Blood pressure targets for the treatment of people with hypertension and cardiovascular disease
Abstract
Background
Hypertension is a prominent preventable cause of premature morbidity and mortality. People with hypertension and established cardiovascular disease are at particularly high risk, so reducing blood pressure below standard targets may be beneficial. This strategy could reduce cardiovascular mortality and morbidity but could also increase adverse events. The optimal blood pressure target in people with hypertension and established cardiovascular disease remains unknown.
Objectives
To determine if 'lower' blood pressure targets (≤ 135/85 mmHg) are associated with reduction in mortality and morbidity as compared with 'standard' blood pressure targets (≤ 140 to 160/ 90 to 100 mmHg) in the treatment of people with hypertension and a history of cardiovascular disease (myocardial infarction, angina, stroke, peripheral vascular occlusive disease).
Search methods
The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials up to February 2017: the Cochrane Hypertension Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1946), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also searched the Latin American and Caribbean Health Science Literature Database (from 1982) and contacted authors of relevant papers regarding further published and unpublished work. There were no language restrictions.
Selection criteria
We included randomized controlled trials (RCTs) with more than 50 participants per group and at least six months follow‐up. Trial reports needed to present data for at least one primary outcome (total mortality, serious adverse events, total cardiovascular events, cardiovascular mortality). Eligible interventions were lower target for systolic/diastolic blood pressure (≤ 135/85 mmHg) compared with standard target for blood pressure (≤ 140 to 160/90 to 100 mmHg).
Participants were adults with documented hypertension or who were receiving treatment for hypertension and cardiovascular history for myocardial infarction, stroke, chronic peripheral vascular occlusive disease or angina pectoris.
Data collection and analysis
Two review authors independently assessed search results and extracted data using standard methodological procedures expected by The Cochrane Collaboration.
Main results
We included six RCTs that involved a total of 9795 participants. Mean follow‐up was 3.7 years (range 1.0 to 4.7 years). Five RCTs provided individual patient data for 6775 participants.
We found no change in total mortality (RR 1.05, 95% CI 0.90 to 1.22) or cardiovascular mortality (RR 0.96, 95% CI 0.77 to 1.21; moderate‐quality evidence). Similarly, no differences were found in serious adverse events (RR 1.02, 95% CI 0.95 to 1.11; low‐quality evidence). There was a reduction in fatal and non fatal cardiovascular events (including myocardial infarction, stroke, sudden death, hospitalization or death from congestive heart failure) with the lower target (RR 0.87, 95% CI 0.78 to 0.98; ARR 1.6% over 3.7 years; low‐quality evidence). There were more participant withdrawals due to adverse effects in the lower target arm (RR 8.16, 95% CI 2.06 to 32.28; very low‐quality evidence). Blood pressures were lower in the lower' target group by 9.5/4.9 mmHg. More drugs were needed in the lower target group but blood pressure targets were achieved more frequently in the standard target group.
Authors' conclusions
No evidence of a difference in total mortality and serious adverse events was found between treating to a lower or to a standard blood pressure target in people with hypertension and cardiovascular disease. This suggests no net health benefit from a lower systolic blood pressure target despite the small absolute reduction in total cardiovascular serious adverse events. There was very limited evidence on adverse events, which lead to high uncertainty. At present there is insufficient evidence to justify lower blood pressure targets (≤ 135/85 mmHg) in people with hypertension and established cardiovascular disease. More trials are needed to answer this question.
PICOs
Plain language summary
Blood pressure targets in people with cardiovascular disease
Review question
We assessed whether lower blood pressure goals are better than standard blood pressure goals for people with high blood pressure who also have heart or vascular problems.
Background
Many people with heart or vascular problems also have high blood pressure. Some clinical guidelines recommend a lower blood pressure goal (135/85 mmHg or lower) in people with previous heart or vascular problems compared with those without (≤140 to 160 mmHg systolic and ≤ 90 to 100 mmHg diastolic are standard blood pressure goals). It is unclear if the lower goals lead to overall health benefits.
Search date
We searched for evidence up to February 2017.
Study characteristics
We included six trials with 9795 participants who were followed‐up for between a year and 4.7 years. We analyzed data to detect differences between lower and standard blood pressure goals on numbers of deaths and serious adverse events (leading to hospital admission).
Key results
We found no differences in total numbers of deaths, heart or vascular deaths or serious harms between lower and standard blood pressure goal approaches. Based on very little information, we found more dropouts due to drug‐related harms in the lower blood pressure target group. The only significant benefit among people in the lower group in the studies analyzed was a slight decrease in total heart or vascular problems, but there was no overall health benefit.
Quality of the evidence
The best available evidence does not support lower blood pressure goals over standard goals in people with elevated blood pressure and heart or vascular problems. More new trials are needed to answer this question. Overall, quality evidence was assessed as low to moderate according to the GRADE assessment.
