What are the differences between the 2020 International Society of Hypertension (ISH) guidelines, the 2017 American College of Cardiology/American Heart Association (ACC/AHA) guidelines, and the 2014 Joint National Committee 8 (JNC 8) guidelines for hypertension management?

From the Guidelines

The 2020 ISH guidelines for hypertension differ from the 2017 ACC/AHA and 2014 JNC 8 guidelines primarily due to variations in blood pressure thresholds and treatment approaches, with ISH focusing on global applicability and resource considerations. The main differences between these guidelines lie in their definitions of hypertension, with ISH using a threshold of ≥140/90 mmHg, whereas ACC/AHA uses a lower threshold of ≥130/80 mmHg 1. This discrepancy is a result of the ISH's emphasis on creating guidelines that can be applied globally, particularly in low-resource settings where more aggressive treatment targets may not be feasible. Key aspects of the ISH guidelines include:

• Definition of hypertension as blood pressure ≥140/90 mmHg
• Essential and optimal standards for treatment, with the essential standard being more suitable for resource-constrained environments
• Treatment initiation thresholds that vary based on cardiovascular risk, with medication recommended for patients with BP ≥140/90 mmHg who have high cardiovascular risk, and delayed pharmacotherapy for lower-risk patients until BP reaches 160/100 mmHg In contrast, the ACC/AHA guidelines recommend antihypertensive drug therapy when SBP 130–139 mm Hg or DBP 80-89 mm Hg and CVD or 10-year atherosclerotic CVD risk ≥10% 1. The JNC 8 guidelines had recommended higher treatment thresholds for older adults (≥150/90 mmHg for those over 60), which neither ISH nor ACC/AHA maintained 2. These differences stem from varying interpretations of clinical evidence, resource considerations, and the intended scope of implementation, with ISH deliberately creating guidelines that could be realistically applied across diverse healthcare systems worldwide. The most recent and highest quality study, published in 2022, highlights the similarities and differences between the 2017 ACC/AHA and 2018 ESC/ESH adult BP guidelines, further emphasizing the need for nuanced approaches to hypertension management 3. Ultimately, the choice of guideline depends on the specific clinical context and resource availability, with the goal of reducing morbidity, mortality, and improving quality of life for patients with hypertension.

From the Research

Differences in Guidelines

• The 2020 ISH guidelines for hypertension differ from the 2017 ACC/AHA and 2014 JNC 8 guidelines in several aspects, including the definition of hypertension, drug treatment, and blood pressure targets 4.
• The 2020 ISH guidelines are more similar to the 2018 ESC/ESH guidelines, with a focus on practical issues related to hypertension management in both high-income and low-income countries 4.
• The guidelines differ in their approach to blood pressure targets, with the 2020 ISH guidelines defining several targets in relation to age, target organ damage, and concomitant disease, whereas the 2017 ACC/AHA guidelines have a more uniform approach 4.

Comparison of Guidelines

• A comparison of the 2017 ACC/AHA and 2018 ESC/ESH guidelines found similarities and differences in their approaches to hypertension management, including the definition of hypertension, drug treatment, and blood pressure targets 5.
• The 2017 ACC/AHA guidelines and the 2018 ESC/ESH guidelines have different recommendations for the use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the treatment of hypertension 6.
• A systematic review found that amlodipine, a calcium channel blocker, is an effective treatment option for patients with hypertension and concomitant diabetes mellitus and/or renal dysfunction, with comparable efficacy to other classes of antihypertensive medications 7.

Blood Pressure Targets

• The 2020 ISH guidelines define several blood pressure targets in relation to age, target organ damage, and concomitant disease, which may be a point of difference with other guidelines 4.
• The use of differential blood pressure targets and rigid "safety boundaries" is not supported by randomized clinical trials and meta-analyses, according to some studies 4.
• The definition of blood pressure targets is an important aspect of hypertension management, and different guidelines may have different approaches to this issue 4, 5.