July 11, 2018

expert reaction to study looking at American blood pressure guidelines and how many people in the USA and China would be classed as having high blood pressure

A new study, published in the BMJ, examines the effect of the 2017 American College of Cardiology/American Heart Association (AHA) hypertension guidelines on the prevalence of hypertension and eligibility for initiation and intensification of treatment in nationally representative populations from the United States and China.

Prof Anna Dominiczak FMedSci, Regius Professor of Medicine, University of Glasgow, said:

“The ACC/AHA Guidelines are not sensible and we should not adopt them in the UK.  They are evidence-based and the team did extensive literature analysis but the issue is with the nomenclature used.  To say a Systolic Blood Pressure (SBP) of 120-129 mmHg and a Diastolic Blood Pressure (DBP) of 80 mmHg is high, is incorrect.  The majority of other international and national guidelines do not have this threshold – indeed such SBP and DBP are considered normal.

“The journal which was first to publish the ACC/AHA Guidelines is Hypertension, journal of the AHA.  As an Editor in Chief of Hypertension, I asked all regional societies of hypertension to submit their response/ debate of the US Guidelines, which we published earlier this year^1,2,3.”

1 Guidelines: Whelton PK, Carey RM, Aronow WS, et al. 017ACC/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:e13–e115. doi: 10.1161/HYP.0000000000000065

2 Comment related to Asian populations: Kario K, Wang J. ‘Could 130/80 mm Hg Be Adopted as the Diagnostic Threshold and Management Goal of Hypertension in Consideration of the Characteristics of Asian Populations?’ Hypertension. 2018;71:979-984. doi: 10.1161/HYPERTENSIONAHA.118.11203

3 URL for entire Guidelines Conversation: http://hyper.ahajournals.org/content/guidelines2017

Prof Francesco Cappuccio, Cephalon Professor of Cardiovascular Medicine & Epidemiology at the University of Warwick, and President of the British and Irish Hypertension Society, said:

“This is an interesting analysis of the likely impact in the USA and China of the implementation of recent American (American College of Cardiology and American Heart Association) hypertension guidelines.  The ACC/AHA guidelines have raised a significant number of comments in response to their publication and will continue to do so.  Last month the new European (European Society of Hypertension and the European Society of Cardiology) hypertension guidelines were presented in short in Barcelona and will be fully launched in Munich at the ESC in August.  Furthermore, NICE is reviewing the guidelines for England and Wales with the plan to release them in September 2019.  So, this paper doesn’t mean any change for the UK just now, but over the next couple of years we’ll find out what it might mean for us.  The new 2018 ESH/ESC Guidelines for Europe – as we understand from the limited release so far – position themselves in a different way, giving the definition of hypertension as a blood pressure of higher than 140/90 mmHg, in contrast with the lower threshold of the US guidelines (which lasses hypertension as blood pressure of higher than 130/80 mmHg).

“The present study projects the impact of just one aspect of the new ACC/AHA guidelines, i.e. the definition of high blood pressure which, in turn, has implication for the definition of prevalence and for the eligibility for drug therapy.  Although the paper takes USA and China as two case studies, the effect would occur in every country in the world if the American threshold is taken up elsewhere, so that at the stroke of a pen we would record more cases of high blood pressure because of a change in threshold, and those increased numbers of people would be offered drug therapy who before were not considered to need it: there would be massive sudden medicalisation and would increase costs for healthcare systems.

“However, will these changes lead to more lives saved?  Perhaps is the answer!  There are many methodological issues to consider when interpreting the ACC/AHA guidelines: they use a mix of evidence-based approach (when available) with best consensus (when not) relying more on observational rather than randomised controlled trial evidence.  Even when RCTs are used, the American guidelines rely on SPRINT, a randomised controlled trial comparing the effect on cardiovascular outcomes of standard targets versus lower targets.  They used a blood pressure device that was never used before in clinical trials (recording lower blood pressures and not allowing for white-coat hypertension) and excluded altogether patients with diabetes from their entry criteria, diabetics who represent a significant bulk of hypertensives in the global population, whose blood pressure control is paramount for the reduction of the burden of CVD.

“The last sentence of the BMJ paper, “The change occurs at the time when both countries have substantial numbers of people who are not aware of having hypertension and who have hypertension that is not controlled even according to the previous standards”, captures one of the most important issues we are facing in the field of hypertension and cardiovascular prevention.  Numerous national surveys (like those in England, the US and Canada) as well as recent global data from the global MMM17 initiative published in the Lancet, highlight that a significant proportion of people do not know they have high blood pressure, and of those who know it, not all take effective medications, and of those who take medications, not all achieve the targets currently recommended.  In other words, healthcare systems around the world still cannot manage to deliver the cardiovascular protection that would derive from implementing current guidelines (however less stringent they may be compared to the new ones).  Furthermore, the affordability of the new guidelines is not clear for different health care systems and the underpinning evidence does not allow us to generalise to the whole population of hypertensives (i.e. to the hundreds of millions of hypertensives with diabetes globally).

“So this new discussion about a new threshold for high blood pressure, in my view, remains an academic debate which will divert attention from the study of more effective healthcare models needed to improve the detection, management and control of hypertension as it is defined today.”

Prof Jeremy Pearson, Associate Medical Director, British Heart Foundation, said:

“The proposed guidelines are evidence-based, but as noted by the authors of this paper would lead to substantial increases in the numbers of people labelled as hypertensive in China or the USA.  In the UK it would probably have a similar effect.  The appetite for adoption in the UK would be slender for this reason alone.  Ultimately, taking a quantitative approach to CVD risk and combining measured blood pressure levels with other risk factor levels (e.g. lipids, obesity) to assess overall individual CVD risk (‘personalised medicine’) before leaping to prescription seems the best way forward.  However, at present the most important needs are to identify individuals with unrecognised high blood pressure (defined by the current cut off) more effectively, and to persuade those who have diagnosed hypertension to adhere to treatments to control it.”

* ‘Impact of 2017 ACC/AHA guidelines on prevalence of hypertension and eligibility for antihypertensive treatment in United States and China: nationally representative cross sectional study’ by Rohan Khera et al. published in the BMJ on Wednesday 11 July 2018. 

Declared interests

None received.