Even Modest Reductions in Blood Pressure Can Lead to Substantial Reductions in Cardiovascular Events
Michael J. Bloch, MD
Associate Professor, University of Nevada School of Medicine
Medical Director, Renown Vascular Care, Renown Institute for Heart and Vascular Health
President, Blue Spruce Medical Consultants, PLLC
Bloch MJ. Commentary: Even modest reductions in blood pressure can lead to substantial reductions in cardiovascular events. Consultant360. Published online October 3, 2021.
Multiple prospective, randomized-controlled studies over the past 3 decades have proven without a doubt that the pharmacological treatment of hypertension leads to significant reductions in cardiovascular (CV) events and that lower achieved blood pressure (BP) translates to lower CV event rates. Often lost in these studies is the magnitude of benefit that can be achieved with even modest reductions in BP.
The Blood Pressure Lowering Treatment Trialists Collaboration (BPLTTC) has been a trusted source of meta-analyses in the field for more than 20 years. The BPLTTC recently published a meta-analysis of 48 randomized-controlled clinical trials of pharmacologic treatment of hypertension, evaluating the effect of a 5-mm Hg reduction in BP.1 This analysis included participant-level data from 344,716 participants with a mean prerandomization BP of 146/84 mm Hg in the 157,728 participants with pre-exiting CV disease and 157/89 mm Hg in the 186,988 participants without pre-existing CV disease. Over a mean 4.15 years, a 5-mm Hg reduction in BP was associated with an approximately 10% reduction in major CV events. Looking at events individually, there was a 13% reduction in stroke, an 8% reduction in ischemic heart disease, a 13% reduction in incident heart failure, and a 5% reduction in CV death. Reductions of similar relative magnitude were seen in patients with and without pre-existing CV disease and regardless of baseline BP. Although, of course, patients with pre-existing CV disease and higher baseline BP had an increased absolute risk of events.
This data builds on a previously published meta-analysis of 123 studies of pharmacological antihypertensive therapy, which included 613,815 participants enrolled in randomized, prospective clinical trials of antihypertensive therapy until 2015.2 In this analysis, a 10-mm Hg reduction in BP reduced the risk of major CV events by 20%, with a 17% reduction in coronary heart disease, a 27% reduction in stroke, a 28% reduction in heart failure, and a 13% reduction in all-cause mortality. Once again, the relative risk reduction was similar regardless of baseline BP or the presence of absence of pre-existing CV disease.
While there remains significant debate about what should be the target or goal BP in treated patients with hypertension, these data suggest that rather than simply concentrating on a specific BP threshold, we need to acknowledge that regardless of baseline BP, even modest reductions in BP, such as can be seen with adding one additional medication or increasing certain lifestyle measures, can have a demonstrable effect on reducing CV risk. When patients ask us why we want to lower their BP, we can cite these data to encourage our patients to be more aggressive with both lifestyle modifications and antihypertensive medications, whether their achieved BP falls below the relatively arbitrary thresholds provided by our guidelines.
These reports also highlight the importance of thinking about both relative and absolute risk reductions in the pharmacologic treatment of hypertension. While the relative reduction in CV events was similar regardless of baseline BP and presence or absence of pre-existing CV disease, the absolute benefits of therapy are clearly higher in patients with higher CV risk, including those with pre-existing CV disease, higher baseline BP, older age, and the presence of other CV disease risk factors. This concept supports the recommendations from the 2017 American College of Cardiology/American Heart Association guidelines that suggest initiating hypertensive medications in higher-risk individuals at lower blood pressures than those with lower overall cardiovascular risk.3
While those of us who treat BP should continue to be frustrated with the overall low rates of BP control in the United States, we should take some solace that our efforts are not in vain. Clearly, even modest reductions in BP, on the order of 5 to 10 mm Hg can lead to meaningful reductions in CV disease risk even if patients do not achieve “goal” BP, particularly in patients at higher baseline CV disease risk.
- The Blood Pressure Lowering Treatment Trialists’ Collaboration. Pharmacological blood pressure lowering for primary and secondary prevention of cardiovascular disease across different levels of blood pressure: an individual participant-level data meta-analysis. Lancet. 2021;397(10285):1625-1636. https://doi.org/10.1016/s0140-6736(21)00590-0
- Ettehad D, Emden CA, Kiran A, et al. Blood pressure lowering for prevention of cardiovascular disease and death. Lancet. 2016;387(10022):957-967. https://doi.org/10.1016/s0140-6736(15)01225-8
- Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018;71(19):e13-e115. https://doi.org/10.1161/hyp.0000000000000065