The importance of properly controlling your blood pressure

The importance of properly controlling your blood pressure

OVERVIEW

  • Hypertension is the main risk factor for cardiovascular disease and is responsible for 20% of deaths worldwide.
  • Early hypertension, before the age of 45, is associated with an increased risk of cardiovascular disease, cognitive decline and premature mortality.
  • Adopting an overall healthy lifestyle (normal weight, not smoking, regular physical activity, moderate alcohol consumption, and a good diet including sodium reduction) remains the best way to maintain adequate blood pressure.

According to the latest data from the Global Burden of Disease Study 2019, excessively high blood pressure was responsible for 10.8 million deaths worldwide in 2019, or 19.2% of all deaths recorded. This devastating impact is a direct consequence of the enormous damage caused by hypertension on the cardiovascular system. Indeed, a very large number of studies have clearly shown that excessive blood pressure, above 130/80 mm Hg (see box for a better understanding of blood pressure values), is closely linked to a significant increased risk of coronary heart disease and stroke.

 

Systolic and diastolic

It is important to remember that blood pressure is always expressed in the form of two values, namely systolic pressure and diastolic pressure. Systolic pressure is the pressure of the blood ejected by the left ventricle during the contraction of the heart (systole), while diastolic pressure is that measured between two beats, during the filling of the heart (diastole). To measure both pressures, the arterial circulation in the arm is completely blocked using an inflatable cuff, then the cuff pressure is allowed to gradually decrease until blood begins to flow back into the artery. This is the systolic pressure. By continuing to decrease the swelling of the cuff, we then arrive at a pressure from which there is no longer any obstacle to the passage of blood in the artery, even when the heart is filling. This is the diastolic pressure. A blood pressure value of 120/80 mm Hg, for example, therefore represents the ratio of systolic (120 mm Hg) and diastolic (80 mm Hg) pressures.

As shown in Figure 1, this risk of dying prematurely from coronary heart disease is moderate up to a systolic pressure of 130 mm Hg or a diastolic pressure of 90 mm Hg, but increases rapidly thereafter to almost 4 times for pressures equal to or greater than 150/98 mm Hg. This impact of hypertension is even more pronounced for stroke, with an 8 times higher risk of mortality for people with systolic pressure above 150 mm Hg and 4 times higher for a diastolic pressure greater than 98 mm Hg (Figure 1, bottom graph). Consequently, high blood pressure is by far the main risk factor for stroke, being responsible for about half of the mortality associated with this disease.


Figure 1. Association between blood pressure levels and the risk of death from coronary heart disease or stroke. From Stamler et al. (1993).

Early hypertension
Blood pressure tends to increase with aging as blood vessels become thicker and less elastic over time (blood circulates less easily and creates greater mechanical stress on the vessel wall). On the other hand, age is not the only risk factor for high blood pressure: sedentary lifestyle, poor diet (too much sodium intake, in particular), and excess body weight are all lifestyle factors that promote the development of hypertension, including in younger people.

In industrialized countries, these poor lifestyle habits are very common and contribute to a fairly high prevalence of hypertensive people, even among young adults. In Canada, for example, as many as 15% of adults aged 20–39 and 39% of those aged 40–59 have blood pressure above 130/80 mm Hg (Figure 2).


Figure 2. Prevalence of hypertension in the Canadian population. Hypertension is defined as systolic pressure ≥ 130 mm Hg or diastolic pressure ≥ 80 mm Hg, according to the 2017 criteria of the American College of Cardiology and the American Heart Association. The data are from Statistics Canada.

This proportion of young adults with hypertension is lower than that observed in older people (three in four people aged 70 and over have hypertension), but it can nevertheless have major repercussions on the health of these people in the longer term. Several recent studies indicate that it is not only hypertension per se that represents a risk factor for cardiovascular disease, but also the length of time a person is exposed to these high blood pressures. For example, a recent study reported that onset of hypertension before the age of 45 doubles the risk of cardiovascular disease and premature death, while onset of hypertension later in life (55 years and older) has a much less pronounced impact (Figure 3). These findings are consistent with studies showing that early hypertension is associated with an increased risk of cardiovascular mortality and damage to target organs (heart, kidneys, brain). In the case of the brain, high blood pressure in young adults has been reported to be associated with an increased risk of cognitive decline at older ages. Conversely, a recent meta-analysis suggests that a reduction in blood pressure with the help of antihypertensive drugs is associated with a lower risk of dementia or reduced cognitive function.

Figure 3. Change in risk of cardiovascular disease (red) or death from all causes (blue) depending on the age at which hypertension begins. Adapted from Wang et al. (2020).

Early hypertension should therefore be considered an important risk factor, and young adults can benefit from managingtheir blood pressure as early as possible, before this excessively high blood pressure causes irreparable damage.

The study of barbershops
In African-American culture, barbershops are gathering places that play a very important role in community cohesion. For health professionals, frequent attendance at these barbershops also represents a golden opportunity to regularly meet Black men to raise their awareness of certain health problems that disproportionately affect them. This is particularly the case with hypertension: African American men 20 years and older have one of the highest prevalence of high blood pressure in the world, with as many as 59% of them being hypertensive. Also, compared to whites, Black men develop high blood pressure earlier in their lives and this pressure is on average much higher.

A recent study indicates that barbershops may raise awareness among African Americans about the importance of controlling their blood pressure and promoting the treatment of hypertension. In this study, researchers recruited 319 African Americans aged 35 to 79 who were hypertensive (average blood pressure approximately 153 mm Hg) and who were regular barbershop customers. Participants were randomly assigned to two groups: 1) an intervention group, in which clients were encouraged to see, in the barbershops, pharmacists specially trained to diagnose and treat hypertension and 2) a control group, in which barbers suggested that clients make lifestyle changes and seek medical attention. In the intervention group, pharmacists met regularly with clients during their barbershop visits, prescribed antihypertensive drugs, and monitored their blood pressure.

After only 6 months, the results obtained were nothing short of spectacular: the blood pressure of the intervention group fell by 27 mm Hg (to reach 125.8 mm Hg on average), compared to only 9.3 mm Hg (to reach 145 mm Hg on average) for the control group. Normal blood pressure (less than 130/80 mm Hg) was achieved in 64% of participants in the intervention group, while only 12% of those in the control group were successful. A recent update of the study showed that the beneficial effects of the intervention were long-lasting, with continued pressure reductions still observed one year after the start of the study.

These reductions in blood pressure obtained in the intervention group are of great importance, as several studies have clearly shown that pharmacological treatment of hypertension causes a significant reduction in the risk of cardiovascular diseases, including coronary heart disease and stroke, as well as kidney failure. This study therefore shows how important it is to know your blood pressure and, if it is above normal, to normalize it with medication or through lifestyle changes.

The importance of lifestyle
This last point is particularly important for the many people who have blood pressure slightly above normal, but without reaching values ​​as high as those of the participants of the study mentioned above (150/90 mm Hg and above). In these people, an increase in the level of physical activity, a reduction in sodium intake, and body weight loss can lower blood pressure enough to allow it to reach normal levels. For example, obesity is a major risk factor for hypertension and a weight loss of 10 kg is associated with a reduction in systolic pressure from 5 mm to 10 mm Hg. This positive influence of lifestyle is observed even in people who have certain genetic variants that predispose them to high blood pressure. For example, adopting an overall healthy lifestyle (normal weight, not smoking, regular physical activity, moderate alcohol consumption, and a good diet including sodium reduction) has been shown to be associated with blood pressure approximately 3 mm Hg lower and a 30% reduction in the risk of cardiovascular disease, regardless of the genetic risk. Conversely, an unhealthy lifestyle increases blood pressure and the risk of cardiovascular disease, even in those who are genetically less at risk of hypertension.

In short, taking your blood pressure regularly, even at a young age, can literally save your life. The easiest way to regularly check your blood pressure is to purchase one of the many models of blood pressure monitors available in pharmacies or specialty stores. Take the measurement in a seated position, legs uncrossed and with the arm resting on a table so that the middle of the arm is at the level of the heart. Two measurements in the morning before having breakfast and drinking coffee and two more measurements in the evening before bedtime (wait at least 2 hours after the end of the meal) generally give an accurate picture of blood pressure, which should be below 135/85 mm Hg on average according to Hypertension Canada.

Aspirin for primary prevention of cardiovascular events?

Aspirin for primary prevention of cardiovascular events?

Updated on January 24, 2019

It is well established that aspirin is beneficial in secondary prevention, that is, for patients who have already suffered a myocardial infarction or stroke or who have a condition such as angina, acute coronary syndrome, or myocardial ischemia, and for those who have undergone coronary artery bypass grafting or coronary angioplasty. It has been suggested that aspirin may also be beneficial in primary prevention, i.e., to prevent cardiovascular events in those who have never had one, but are at risk. For the last few decades, aspirin has been used at low doses to prevent myocardial infarction and stroke; however, a recent study indicates that this drug does not prevent a first heart attack or stroke in people with moderate cardiovascular risk. In another study, this time of people with type 2 diabetes, taking aspirin modestly reduced the risk of cardiovascular events, but increased the risk of serious bleeding.

Primary prevention in people at moderate risk
Low-dose aspirin (100 mg/day) does not prevent a first heart attack or stroke in people at moderate risk of developing cardiovascular disease according to the ARRIVE study (Aspirin to Reduce Risk of Initial Vascular Events), published in The Lancet in August 2018. Aspirin has been tested in primary prevention over an average of 5 years, with 12,546 people living in the United Kingdom, Poland, Germany, Italy, Ireland, Spain and the USA. During these years, participants who took 100 mg of aspirin daily did not have significantly fewer vascular events than those who took a placebo [269 participants (4.3%) vs. 281 (4.5%); p=0.6038]. There were fewer vascular events than expected in this study, suggesting that participants had low cardiovascular risk rather than moderate risk. Gastrointestinal bleeding, which was mostly mild, was significantly higher in the aspirin group than in the placebo group [61 participants (0.97%) vs. 29 (0.46%); p=0007].

The authors of the ARRIVE study conclude that “The use of aspirin remains a decision that should involve a thoughtful discussion between a clinician and a patient, given the need to weigh cardiovascular and possible cancer prevention benefits against the bleeding risks, patient preferences, cost, and other factors. The ARRIVE data must be interpreted and used in the context of other studies, which have tended to show a reduction primarily in myocardial infarction, with less of an effect on total stroke (including both ischaemic and haemorrhagic stroke).

Primary prevention in people with diabetes
Aspirin has been tested for primary prevention in 15,480 people with type 2 diabetes, who are therefore at increased risk of developing or dying from cardiovascular disease. During the seven years of the randomized study, people who took 100 mg of aspirin daily had significantly fewer serious vascular events than those who took a placebo [658 participants (8.5%) vs. 743 (9.6%)]. In contrast, major bleeding was greater in the aspirin group than in the placebo group [314 participants (4.1%) vs. 245 (3.2%)]. There was no significant difference between the group that took aspirin and the placebo group for gastrointestinal cancer incidence [157 participants (2.0%) vs. 158 (2.0%)] or any type of cancer [897 participants (11.6%) vs. 887 (11.5%)]. The authors of this study conclude that the benefits of aspirin for people with diabetes are largely outweighed by the risk of bleeding.

Aspirin for prevention in the elderly
The effects of daily low-dose aspirin were evaluated specifically in the elderly in the ASPREE study (Aspirin in Reducing Events in the Elderly), the results of which were published as three articles in the New England Journal Of Medicine (see here, here, and here). The study enlisted 19,114 Australians and Americans aged 70 or older who did not have cardiovascular disease, dementia, or physical disability. Participants were randomly assigned to take a 100 mg enteric-coated aspirin or placebo tablet daily for 5 years. The primary endpoint was a composite endpoint including death, dementia, and persistent physical disability. Secondary endpoints included severe bleeding and cardiovascular disease (nonfatal myocardial infarction, fatal coronary heart disease, fatal or nonfatal stroke, hospitalization for heart failure).

Aspirin did not prolong disability-free survival in the elderly and did not decrease the risk of cardiovascular disease, but it increased the rate of serious bleeding compared with placebo. The composite rate of mortality, dementia, and persistent physical disability was 21.5 and 21.2 events per 1,000 person-years in the group who took aspirin and in the placebo group, respectively. The rates of cardiovascular events were 10.7 and 11.3 events per 1,000 person-years in the aspirin group and the placebo group, respectively. The rate of serious bleeding was significantly higher (P <0.001) in the aspirin group (8.6 events per 1,000 person-years) than in the placebo group (6.2 events per 1,000 person-years). Finally, the all-cause mortality rate was higher in the aspirin group than in the placebo group, a result mainly attributable to deaths from cancer. Since an increase in mortality has not been observed in previous studies on aspirin used for prevention, this unexpected result should be interpreted with caution according to the authors.

Systematic review and meta-analysis
A synthesis of 13 randomized controlled trials of aspirin for primary prevention of cardiovascular disease, including the 3 major trials in 2018, was published in January 2019 in JAMA. All studies included 164,225 participants aged 53 to 74 and a follow-up of 1,050,511 person-years. This meta-analysis confirms that aspirin is associated with a decreased risk of cardiovascular events (cardiovascular mortality, nonfatal myocardial infarction, nonfatal stroke) and an increased risk of major bleeding. Aspirin was associated with an 11% reduction in relative risk (absolute risk reduction of 0.38%) of cardiovascular events and a 43% greater relative risk of major bleeding (absolute risk increase of 0.47%). As a result, 265 people will need to be treated with aspirin for 5 years to prevent a cardiovascular event, but one in 210 treated people will experience major bleeding. Because of the unfavourable benefit-to-disadvantage ratio, the European guidelines do not recommend taking aspirin until cardiovascular disease occurs (secondary prevention), i.e., at a time when the benefits outweigh the risks of adverse effects. On the other hand, the US Preventive Services Task Force (USPSTF) recommends improving the benefit-harm ratio for aspirin in primary prevention by estimating the risks of cardiovascular events and bleeding for each patient, considering the potential longer-term benefits of aspirin for the prevention of colorectal cancer, and carefully discussing with patients the balance between the risks of vascular and haemorrhagic events.