How low should blood pressure go? Science has the answer

To better understand the impact of different treatment goals, researchers analyzed data from the Systolic Blood Pressure Intervention Trial (SPRINT), the National Health and Nutrition Examination Survey (NHANES), and other published studies. They used this information to model lifetime health outcomes, including heart attack, stroke, and heart failure, for patients with systolic blood pressure targets of <120 mm Hg, <130 mm Hg, and <140 mm Hg.

Because blood pressure medications can cause side effects, the team also evaluated the risk of serious complications linked to treatment. Their model included both the potential benefits of preventing cardiovascular events and the possible harms associated with medication use.

Accounting for Real-World Measurement Errors

The researchers also incorporated common inaccuracies in blood pressure readings into their analysis. These errors reflect what is often seen in routine clinical settings and can influence treatment decisions and outcomes.

Benefits and Risks of Intensive Blood Pressure Control

Even after factoring in these real-world measurement errors, the model showed that targeting a systolic blood pressure below 120 mm Hg prevented more cardiovascular events than aiming for 130 mm Hg. This included reductions in heart attacks, strokes, and heart failure.

However, the more aggressive target was not without downsides. Patients faced a higher likelihood of treatment-related side effects, including falls, kidney injury, hypotension, and bradycardia. In addition, pursuing the lower target increased overall healthcare costs due to greater use of antihypertensive medications and more frequent doctor visits.

Cost-Effectiveness of Lower Blood Pressure Goals

Despite the added risks and expenses, the researchers found that the <120 mm Hg target remained cost-effective when compared with higher targets under typical conditions. The estimated cost was $42,000 per quality-adjusted life-year gained, a commonly used measure of value in healthcare.

Experts Weigh In on Treatment Decisions

"This study should give patients at high cardiovascular risk and their clinicians more confidence in pursuing an intensive blood pressure goal," said lead author Karen Smith, PhD, an investigator at the Department of Orthopedic Surgery at Brigham and Women's Hospital, a founding member of the Mass General Brigham healthcare system. "Our findings suggest the intensive <120 mm Hg target prevents more cardiovascular events and provides good value, and this holds true even when measurements aren't perfect."

Smith emphasized that these findings apply at the population level and may not be appropriate for every individual. "Our results examine the cost-effectiveness of intensive treatment at the population level. However, given the additional risk of adverse events related to antihypertensives, intensive treatment will not be optimal for all patients. Patients and clinicians should work together to determine the appropriate medication intensity based on patient preferences."

Study Authors and Funding

In addition to Smith, Mass General Brigham authors include Thomas Gaziano. Other contributors to the study include Alvin Mushlin, David Cutler, Nicolas Menzies, and Ankur Pandya.

The research was funded by the National Science Foundation and the National Institute of Neurological Disorders and Stroke.