NEW ORLEANS, LA — A new large network meta-analysis of randomized trials of hypertension patients reports that risk of CVD and premature death was much lower in patients who attained a target systolic blood pressure below current recommendations[1].
“There was a linear association between the [mean] achieved systolic blood pressure and risk of cardiovascular disease and total mortality” during a mean follow-up of 3.6 years, and “the lowest risk was at a systolic blood pressure of 120 to 124 mm Hg, which is much lower than current guideline recommendations of below 140 mm Hg,” senior author Dr Jiang He (Tulane University, New Orleans, LA) told heartwire from Medscape.
This network meta-analysis of 42 randomized clinical trials and more than 140,000 patients “supports more intensive SBP control among adults with hypertension and suggests the need for revising the current clinical guidelines for management of hypertension,” Dr Joshua D Bundy (Tulane University, New Orleans, LA) and colleagues write in the study, which was published May 31, 2017 in JAMA Cardiology.
After “poor consensus and worrisome uncertainty” about “the ideal target for one of the most important risk factors for CVD,” the Systolic Blood Pressure Intervention Trial (SPRINT), the Heart Outcomes Prevention Evaluation-3 (HOPE-3) trial, and now this network meta-analysis “are bringing clarity that should be endorsed by updated guideline statements,” Drs Clyde W Yancy and Robert O Bonow (Feinberg School of Medicine, Northwestern University, Chicago, IL), deputy editor and editor of JAMA Cardiology, respectively, write in an accompanying editorial[2].
Lowering systolic blood pressure to 120 to 124 mm Hg in a clinical trial is “likely akin to systolic blood pressure <130 mm Hg in clinical practice,” they add. Thus, clinicians “should transition from the interrogative question of what treatment target is appropriate to the declarative statement that lower, preferably less than 130 mm Hg if safely attainable, is better,” according to Yancy and Bonow.
Optimal Target Is Controversial
Although clinical trials have demonstrated that lowering blood pressure reduces the risk of CVD and premature death, some post hoc analyses of hypertension-treatment trials have reported that there is a J-shaped association between achieved blood pressure and poor cardiovascular outcomes and risk of death. On the other hand, SPRINT suggested that intensive treatment to a target of <120 mm Hg rather than <140 mm Hg was better, but that trial did not enroll patients with type 2 diabetes or with previous stroke.
“Finding the optimal SBP target could have far-reaching implications for the reduction of CVD and premature death in general populations,” Bundy and colleagues write.
They performed a network meta-analysis in which they combined data from randomized clinical trials to examine the association between different levels of SBP reduction and the risk of major CVD, stroke, CHD, CVD mortality, and all-cause mortality.
They identified 42 randomized trials with a combined 144,220 hypertensive individuals with diverse comorbidities who were followed for a mean of 3.6 years (range 6 months to >8 years). Thirty trials included patients with type 2 diabetes.
Patients were classified into 10 levels of achieved systolic BP, which ranged from <120 mm to >160.
There was a linear relationship between attained systolic blood pressure levels and risk of CVD or death.
A systolic blood pressure of 120 to 124 mm Hg was associated with the lowest risk for major CVD, CHD, CVD mortality, and all-cause mortality, whereas a systolic blood pressure of <120 mm Hg was associated with the lowest risk for stroke.
HR (95% CI) for CVD, Death for Achieved BP 120-124 mm Hg BP vs Higher Achieved BP*
| Higher Achieved BP | CVD, HR (95% CI) | Death, HR (95% CI) |
|---|---|---|
| 130–134 | 0.71 (0.60–0.83) | 0.73 (0.58–0.93) |
| 140–144 | 0.58 (0.48–0.72) | 0.59 (0.45–0.77) |
| 150–154 | 0.46 (0.34–0.63) | 0.51 (0.36–0.71) |
>160 |
0.35 (0.26–0.51) | 0.47 (0.32–0.67) |
*After a mean of 3.6 years of follow-up
Waiting for New Guidelines
In 2015, the National Heart, Lung, and Blood Institute (NHLBI) handed off the task of guideline writing to the American College of Cardiology and the American Heart Association (ACC/AHA), Dr He noted. Then the JNC 8 report was released, which is “not an NHBLI-sanctioned report and does not reflect the views of NHLBI.”
JNC 8 relaxed the blood-pressure targets, he noted, using evidence from the 2010 Action to Control Cardiovascular Risk in Diabetes-Blood Pressure (ACCORD BP) trial (where, in patients with type 2 diabetes at high risk for CV events, targeting SBP <120 mm Hg did not reduce rates of nonfatal MI, nonfatal stroke, or CV mortality when compared with a target SBP <140 mmHg).
Dr Paul K Whelton (Tulane University School of Public Health and Tropical Medicine), a coauthor of the current study, is chair of the upcoming ACC/AHA hypertension treatment guidelines, Dr He noted. The guidelines are currently in the review stage and are expected to be published by the end of this year or beginning of next year and will clearly “take into consideration our study,” as well as data from newer studies such as SPRINT, he said.
In the meantime, “the overall evidence really shows that systolic blood pressure can be below 140 at least, below 130,” said Dr He.
Although SPRINT excluded patients with type 2 diabetes or prior stroke, these patients were included in some of the clinical trials in the current network meta-analysis, so the findings are more generalizable. However, they were not able to do a subgroup analysis, which is one trial limitation, he admitted.
“I think 130 mm Hg is a reasonable goal,” He said. They published a paper last year in Circulation that showed that worldwide, “using 140 mm Hg as the cut point, only about 17% of hypertensive patients have their blood pressure controlled.” At a much lower goal of 125 mm Hg, uncontrolled blood pressure would be “huge.”
The researchers are conducting two large clinical trials in China that have designs similar to SPRINT, according to He, except that one is including patients with stroke and the other patients with type 2 diabetes.
The authors and editorialists report they have no relevant financial relationships.
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