What evidence supports decreasing the maximum normal Blood Pressure (BP) levels in the definition of Hypertension (HTN) over the last couple of decades?

From the Guidelines

The definition of hypertension has evolved to include lower blood pressure thresholds, with the most recent guidelines recommending a definition of 130/80 mmHg, as evidenced by the 2020 U.S. Department of Veterans Affairs/U.S. Department of Defense clinical practice guideline 1. This change is supported by studies such as the SPRINT trial, which demonstrated cardiovascular benefits from more intensive blood pressure control 1. The implications of this new definition are significant, with an estimated 14% of the adult U.S. population (or 31 million additional Americans) meeting the criteria for hypertension 1. Key points to consider include:

• The continuous relationship between blood pressure and adverse outcomes without a clear threshold 1
• The importance of routine screening to diagnose hypertension, particularly in younger patients and African American persons 1
• The need for improved risk stratification strategies to identify individuals with intermediate range blood pressure levels who may benefit from intensive blood pressure control 1
• The potential benefits of earlier intervention, including lifestyle modifications or pharmacological interventions, to prevent target organ damage 1 The most recent guideline from the World Health Organization also supports the use of lower blood pressure thresholds for initiating pharmacological therapy, with a focus on increasing the hypertension control rate worldwide 1. Overall, the evidence supports the use of lower blood pressure thresholds for defining hypertension, with the goal of identifying at-risk individuals earlier and implementing effective interventions to improve cardiovascular health and reduce morbidity and mortality.

From the Research

Definition of Hypertension

• The definition of hypertension has undergone changes over the last couple of decades, with a decrease in the maximum normal Blood Pressure (BP) levels 2, 3.
• The 2017 American College of Cardiology (ACC)/American Heart Association (AHA) guidelines define hypertension as a systolic blood pressure of 130 mm Hg or higher, or a diastolic blood pressure of 80 mm Hg or higher 2, 3.
• This change in definition has led to an increase in the prevalence of patients with hypertension, with an estimated 116 million adults in the US and over 1 billion adults worldwide affected by the condition 2.

Rationale for Decreasing BP Levels

• The decision to decrease the maximum normal BP levels was based on the association between hypertension and increased risk of cardiovascular disease (CVD) events, such as coronary heart disease, heart failure, and stroke 2, 4.
• Randomized clinical trials have established the efficacy of BP lowering in reducing the risk of CVD morbidity and mortality, with an SBP reduction of 10 mm Hg decreasing the risk of CVD events by approximately 20% to 30% 2.
• The goal of treatment is to reduce overall blood pressure to below 140/90 mmHg, with a more optimal goal of 130/80 mmHg 5.

Impact of Changing Guidelines

• The 2017 ACC/AHA guidelines are expected to significantly increase the prevalence of patients with hypertension, particularly in higher-risk patient cohorts 3.
• Patients newly reclassified as having hypertension based on the revised guidelines have a similar risk of adverse cardiovascular events as those with hypertension based on prior guidelines 3.
• The changing guidelines have led to an increased focus on lifestyle modification and first-line therapies, including thiazide or thiazide-like diuretics, angiotensin-converting enzyme inhibitors, and calcium channel blockers 2, 5.