Chief complaint: X. Past medical history: hypertension and others. History of present illness: Y.
How many times have we heard this in emergency department patient encounters? The chief complaint, history of present illness, and pertinent “others” in the past medical history are certainly paramount data points in deciding the proper diagnostic and management strategies, but listing hypertension as one of those points is of limited utility in most emergency department presentations because:
- the definition of hypertension is not well defined and is a moving target.
- the scope of hypertension is unknown. It is also difficult to identify true v. quoted prevalence and who is optimally treated.
- the presence of a past medical history of hypertension has limited diagnostic value (poor positive and negative likelihood ratios).
To properly define hypertension, it is important to discuss how to diagnose it accurately. Correctly measuring blood pressure is often problematic because of the myriad confounders influencing blood pressure at any time. The patient's emotional demeanor, talking during blood pressure recording, measuring an unsupported arm, lacking back support, and having crossed legs and a full bladder can all increase systolic pressure by more than 10 mm Hg. (Am J Hypertens. 1998;11:203; Perm J. 2009;13:51; http://bit.ly/376xwf9; Can J Cardiol. 2018;34:506.)
It is universally agreed that systolic blood pressure should be recorded at auscultation of Korotkoff phase I, but the proper recording of the diastolic values is often debated as either Korotkoff phase IV or V sounds, especially among certain patient populations. (Perm J. 2009;13:51; http://bit.ly/376xwf9.)
Another significant challenge when defining hypertension is that values for hypertension and treatment thresholds are moving targets that change frequently, with a variety of different organizations often failing to reach a consensus. The hypertension cutoff can also vary with age, sex, comorbidities, and the modality by which blood pressure is measured (automated office v. oscillation). (Eur Heart J. 2018;39:3021.)
The quoted prevalence of hypertension in the United States differs significantly depending on whether one looks at primary care or ED population data. Its prevalence in primary care has been consistently quoted at approximately 30 percent, with the prevalence among those 50 and older surpassing 50 percent. (MMWR Morb Mortal Wkly Rep. 2016;65:1261; http://bit.ly/34Oi7i0.) The rates quoted in the ED population are traditionally higher than those of the general population. (NCHS Data Brief. 2011;:1; http://bit.ly/34KzArg.)
Adding more confusion to prevalence rates is that a significant proportion of the population that has hypertension is not aware of the disease and is not treated. And many of those treated do not achieve disease control. (Circulation. 2019;139:e56; http://bit.ly/35J8Cll.)
Approximately one quarter of those with hypertension were unaware that they were hypertensive, and approximately one-third of those who were aware were not being treated with antihypertensive agents. And only two-thirds of those on regular antihypertensive treatment had their hypertension controlled. (JAMA. 2015;314:1955; http://bit.ly/35Evr9L.) One could debate the true significance of a past medical history of hypertension in those patients who achieve ideal blood pressure control with medication.
Hypertension is an important and common risk factor in the development of a majority of cardiovascular diseases, and risk factor identification and modification are an essential part of preventive medicine. Acute care in the ED, however, is arguably less focused on preventive primary care than on diagnosing life-threatening diseases. A past medical history of hypertension in this context as a significant piece of the diagnostic puzzle has limited application in the acute care setting.
We focused on only the most common and serious cardiovascular disease, acute coronary syndrome (ACS). The diagnostic impact of a past medical history of hypertension on other significant cardiovascular diseases is highlighted by their positive and negative likelihood ratios in the table.
Acute coronary syndrome can manifest in myriad presentations in the ED. Few historical elements have enough sensitivity and specificity to diagnose or rule out ACS sufficiently, and a past medical history of hypertension is no exception, as highlighted by the positive and negative likelihood ratios tethering close to 1. (J Am Coll Cardiol. 2018;71:606; http://bit.ly/35L0EYK.) In fact, many of the clinical decision rules and guidelines acknowledge the lack of utility of a past medical history of hypertension in the ED diagnosis of ACS by omitting it in patients of certain ages, completely ignoring it, or assigning it a negligible value. (J Am Coll Cardiol. 2018;71:606; http://bit.ly/35L0EYK.)
Aristotle said it is the mark of an educated mind to be able to entertain a thought without accepting it. The presence or absence of a past medical history of hypertension does not add value to the investigation strategy of most if not all cardiovascular ED presentations, and it should not influence the diagnostic approach.
Clockwise from top left:Dr. Nemethis an emergency physician and trauma team leader at McGill University Health Center, Montreal General Hospital, and Montreal Children's Hospital and an associate professor of emergency medicine and the director of the trauma fellowship at McGill University in Montreal. Dr. Maghrabyis an emergency physician at King Fahd Hospital of the University Al-Khobar, Imam Abdulrahman Bin Faisal University (IAU) in Saudi Arabia. Dr. Lavigueuris an emergency physician presently training in critical care at Université de Montréal. Follow him on Twitter @motorcycleERdoc. Dr. Maneshiis a senior resident at McGill. Follow her on Twitter @A_Maneshi. Dr. Russellis a senior resident at McGill University.