Understanding the Differences Between American and European Blood Pressure Guidelines

Table of Contents

• Introduction: Why Blood Pressure Guidelines Matter
• How the Guidelines Were Developed
• Blood Pressure Measurement Standards
• Blood Pressure Classification Systems
• Patient Evaluation Process
• Cardiovascular Risk Assessment
• When to Start Medication
• Lifestyle Intervention Recommendations
• Key Similarities and Differences
• What This Means for Patients
• Recommendations for Future Guidelines
• Source Information

Introduction: Why Blood Pressure Guidelines Matter

High blood pressure (hypertension) represents one of the most significant public health challenges worldwide, affecting nearly half of American adults according to recent estimates. Proper management of this condition prevents heart attacks, strokes, kidney disease, and other serious complications. In 2017 and 2018, two major guideline documents were published: the American College of Cardiology/American Heart Association (ACC/AHA) guideline and the European Society of Cardiology/European Society of Hypertension (ESC/ESH) guideline.

These documents provide evidence-based recommendations for healthcare professionals on how to prevent, detect, evaluate, and manage high blood pressure. While developed through rigorous processes and extensive peer review, the guidelines show some important differences that patients should understand, particularly regarding when hypertension is diagnosed and when medication should be started.

The most noticeable difference between the two guidelines is the blood pressure cut points recommended for diagnosing hypertension. The American guideline recommends a more intensive approach to treatment in some cases. Despite these differences, there is substantial agreement between the recommendations, with greater consistency than seen in previous versions of these guidelines.

How the Guidelines Were Developed

Both guidelines followed rigorous development processes with some important differences in their approaches. The ACC/AHA guideline was created by a 21-member writing committee that included primary and specialty care physicians, epidemiologists, a nurse, a physician assistant, a pharmacist, and two patient representatives. Committee members were chosen to represent the two principal sponsors and nine collaborating professional societies.

Notably, the ACC/AHA required committee members to have no relationships with blood pressure-related commercial entities. The ESC/ESH guideline was developed by a 28-member committee of physicians and nurses from 14 European countries, with half selected by each society. Unlike the American guideline, the European committee required disclosure of commercial relationships rather than prohibiting them entirely.

The ACC/AHA process specified that systematic reviews and meta-analyses be conducted by an independent Evidence Review Committee, resulting in 448 detailed evidence tables published alongside the guideline recommendations. The ESC/ESH committee had the option to commission additional evidence reviews but determined that existing published systematic reviews provided sufficient evidence for decision-making.

Both guidelines underwent extensive peer review and required final approval by their sponsoring organizations' governing boards. The ACC/AHA guideline provides 106 formal recommendations, while the ESC/ESH provides 122 recommendations. Each recommendation in both guidelines includes a class of recommendation (indicating strength) and a level-of-evidence designation, with both committees voting on the wording and grading of each recommendation.

Blood Pressure Measurement Standards

Accurate blood pressure measurement is crucial for proper diagnosis and management, as measurement errors represent a major source of misclassification. Both guidelines emphasize the importance of using validated devices and multiple readings for diagnosis and management of hypertension.

The ACC/AHA recommends averaging office blood pressure readings using the same approach as previous guidelines: ≥2 readings on ≥2 occasions. They also recommend confirming office hypertension with out-of-office measurements. The ESC/ESH recommends 3 readings for office measurement, with additional readings when the first two differ by >10 mm Hg or when blood pressure is unstable due to arrhythmia.

Both guidelines recommend out-of-office measurements to identify masked hypertension (normal office readings but high outside readings) and white coat hypertension (high office readings but normal outside readings). The guidelines provide slightly different treatment guidance for these conditions while acknowledging the uncertainty of such recommendations.

The ACC/AHA provides corresponding values for office and out-of-office measurements across a range from 120/80 mm Hg to 160/100 mm Hg. The ESC/ESH provides only the cutoff values for diagnosing hypertension for home and ambulatory monitoring, but these values align with those in the ACC/AHA guideline:

Blood Pressure Classification Systems

The most significant difference between the two guidelines lies in their blood pressure classification systems and the cut points for diagnosing hypertension. The ACC/AHA proposes categories for normal blood pressure, elevated blood pressure, and two stages of hypertension, using a cut point of systolic blood pressure (SBP) ≥130 mm Hg and/or diastolic blood pressure (DBP) ≥80 mm Hg for identifying hypertension.

This represents a change from the previous 2003 guideline, which used SBP ≥140 mm Hg and/or DBP ≥90 mm Hg except in adults with diabetes or chronic kidney disease, where the cut point was SBP ≥130 mm Hg and/or DBP ≥80 mm Hg. The ESC/ESH classifies blood pressure into optimal, normal, high normal, three grades of hypertension, and isolated systolic hypertension, maintaining the SBP ≥140 mm Hg and/or DBP ≥90 mm Hg cut points from their 2013 guideline.

Based on National Health and Nutrition Examination Survey data from 2011-2014, the ACC/AHA reclassification would increase hypertension prevalence from 32% to 46% among US adults—approximately a 14% increase. This analysis likely overestimates true prevalence since blood pressure was measured only on a single occasion without confirmation by out-of-office readings.

The ACC/AHA categorization is simpler and captures more blood pressure-related cardiovascular risk but presents challenges because it designates hypertension in a higher percentage of adults and requires assessment of underlying cardiovascular disease risk for treatment decisions, especially in stage 1 hypertension. The ESC/ESH system has more categories but provides a simpler approach to medication decisions.

Patient Evaluation Process

Both guidelines recommend similar approaches to patient evaluation, including:

• Personal and family medical history
• Physical examination including blood pressure measurement
• Basic laboratory testing

The specific laboratory tests recommended show some differences:

Both guidelines recommend:

• Fasting blood glucose
• Blood/serum sodium and potassium
• Lipid profile (cholesterol testing)
• Serum creatinine/estimated glomerular filtration rate (kidney function)
• Urinalysis
• ECG (electrocardiogram)

ACC/AHA only recommends:

• Complete blood count
• Serum calcium
• Thyroid stimulating hormone

ESC/ESH only recommends:

• Hemoglobin/hematocrit
• Blood uric acid
• Glycated hemoglobin A1c (long-term blood sugar measure)
• Liver function tests
• Urine protein test or urinary albumin-to-creatinine ratio

Optional tests in the ACC/AHA guideline include echocardiogram, uric acid, and urinary albumin-to-creatinine ratio. The ESC/ESH guideline additionally mentions echocardiography, carotid ultrasound, pulse wave velocity, ankle-brachial index, cognitive function testing, and brain imaging as additional tests for identifying hypertension-mediated organ damage.

Cardiovascular Risk Assessment

Cardiovascular disease (CVD) risk assessment helps identify individuals at increased risk for heart attacks, strokes, kidney damage, and death related to hypertension. Both guidelines recommend CVD risk assessment to complement blood pressure levels when making treatment decisions, with the ESC/ESH also emphasizing its importance for considering additional interventions like statins and antiplatelet therapies.

The guidelines differ in their risk estimation methods:

ACC/AHA Approach:

• Presence of cardiovascular disease automatically indicates high risk
• For adults 40-79 without CVD, uses Pooled Cohort Equations to estimate 10-year atherosclerotic cardiovascular disease (ASCVD) risk
• Risk estimator considers age, blood pressure, cholesterol levels, diabetes history, smoking status, and current medications
• Uses ≥10% and <10% 10-year ASCVD risk categories
• Hypertension with diabetes, chronic kidney disease, or age ≥65 years is considered a marker for higher risk
• Recommends lifetime risk assessment for adults under 40

ESC/ESH Approach:

• Uses four categories of CVD risk
• Adults with existing CVD, diabetes, very high risk factors, or kidney disease are considered at high or very high risk
• For others, uses Systematic Coronary Risk Evaluation (SCORE) system to estimate 10-year CVD mortality risk
• SCORE considers age, sex, cholesterol, smoking status, and systolic blood pressure
• Emphasizes considering hypertension-mediated organ damage in risk assessment
• Includes heart rate >80 beats/minute as a cardiovascular risk factor

Both guidelines acknowledge challenges with using and interpreting risk estimation tools but emphasize their importance for personalized treatment decisions.

When to Start Medication

The guidelines differ significantly in their recommendations for when to initiate antihypertensive drug therapy:

ACC/AHA Recommendations:

• Drug therapy recommended for all adults with SBP ≥140 mm Hg or DBP ≥90 mm Hg, regardless of cardiovascular risk
• Also recommended for approximately 30% of adults with stage 1 hypertension (SBP 130-139 mm Hg or DBP 80-89 mm Hg) who are at higher CVD/ASCVD risk
• This approach particularly affects older patients since age is a strong risk factor
• For adults over 80 with untreated hypertension, recommends considering treatment only when office SBP is ≥160 mm Hg

ESC/ESH Recommendations:

• Immediate drug therapy for high-risk or very-high-risk patients with SBP ≥140 mm Hg or DBP ≥90 mm Hg who have CVD, renal disease, or hypertension-mediated organ damage
• For low or moderate risk patients with these blood pressure levels, recommends lifestyle intervention first, adding drugs if BP not controlled after 3 months
• Drug therapy may be considered for adults with SBP 130-139 mm Hg or DBP 85-89 mm Hg only if they have CVD, particularly coronary artery disease
• Adults over 80 with untreated hypertension should only be considered for treatment when office SBP is ≥160 mm Hg

Lifestyle Intervention Recommendations

Both guidelines identify lifestyle modification as the cornerstone for preventing and treating hypertension, since unhealthy diet, physical inactivity, and alcohol use contribute significantly to high blood pressure in many adults.

ACC/AHA Lifestyle Recommendations:

• Healthy diet, especially Dietary Approaches to Stop Hypertension (DASH) diet
• Weight loss for overweight/obese adults
• Dietary sodium reduction
• Increased dietary potassium intake
• Regular physical activity
• Alcohol moderation or abstinence

ESC/ESH Lifestyle Recommendations:

• Healthy diet, especially Mediterranean diet
• Weight loss for overweight/obese adults
• Dietary sodium reduction
• Regular physical activity
• Alcohol moderation
• Smoking cessation

Both guidelines emphasize that these lifestyle interventions are fundamental for both prevention and management of hypertension and should be encouraged for all patients, regardless of whether they require medication.

Key Similarities and Differences

While the guidelines show many areas of agreement, several important differences exist that patients should understand:

Areas of Agreement:

• Emphasis on accurate blood pressure measurement using validated devices
• Importance of out-of-office measurements to confirm diagnosis
• Comprehensive patient evaluation including history, physical exam, and laboratory testing
• Central role of lifestyle modifications as foundation of treatment
• Need for cardiovascular risk assessment to guide treatment decisions
• Similar blood pressure treatment goals for most patients
• Recommendations for specific medication classes based on patient characteristics

Key Differences:

• Diagnostic thresholds: ACC/AHA uses ≥130/80 mm Hg while ESC/ESH uses ≥140/90 mm Hg
• Treatment initiation: ACC/AHA recommends medication for high-risk stage 1 hypertension patients, while ESC/ESH reserves medication for mostly stage 2 patients or those with specific conditions
• Risk assessment tools: Different systems (Pooled Cohort Equations vs. SCORE)
• Laboratory testing: Some variations in recommended tests
• Classification system: ACC/AHA uses 4 categories while ESC/ESH uses 7 categories

What This Means for Patients

These guideline differences have practical implications for patients:

Patients diagnosed under the ACC/AHA criteria might be labeled with hypertension earlier and potentially start medication sooner, particularly if they have other risk factors. This earlier intervention could prevent future complications but also means more people taking medications, with associated costs and potential side effects.

Under the ESC/ESH approach, patients might have a longer period of lifestyle intervention before starting medication unless they have very high blood pressure or additional risk factors. This approach might reduce medication use but could delay treatment in some cases where earlier intervention might be beneficial.

The different risk assessment methods might lead to different treatment recommendations for the same patient depending on which system their healthcare provider uses. Patients with borderline blood pressure readings might receive different advice based on which guideline their doctor follows.

Despite these differences, both guidelines agree on the most important aspects of hypertension management: accurate measurement, comprehensive evaluation, lifestyle modification as foundation, and personalized treatment based on individual risk profile.

Recommendations for Future Guidelines

The authors of this comparison article provide several recommendations for future guideline development:

1. Increased harmonization: Future guidelines should work toward greater consistency in recommendations, particularly regarding diagnostic thresholds and treatment initiation criteria
2. Standardized processes: Development processes should be more aligned across different guideline committees
3. Clear communication: Guidelines should provide clear explanations for areas of disagreement and the evidence supporting different approaches
4. Patient involvement: Continued inclusion of patient representatives in guideline development processes
5. Implementation support: Guidelines should be accompanied by practical tools and resources to support implementation in clinical practice

Greater harmonization between US and European guidelines would help emphasize the commonality of their core recommendations and could catalyze practice changes leading to improved prevention, awareness, treatment, and control of hypertension worldwide.

Source Information

Original Article Title: Harmonization of the American College of Cardiology/American Heart Association and European Society of Cardiology/European Society of Hypertension Blood Pressure/Hypertension Guidelines: Comparisons, Reflections, and Recommendations

Authors: Paul K. Whelton, MB, MD, MSc; Robert M. Carey, MD; Giuseppe Mancia, MD; Reinhold Kreutz, MD; Joshua D. Bundy, PhD, MPH; Bryan Williams, MD

Publication: Circulation. 2022;146:868–877. DOI: 10.1161/CIRCULATIONAHA.121.054602

Note: This patient-friendly article is based on peer-reviewed research originally published in Circulation, European Heart Journal, and Journal of the American College of Cardiology.