Article Type : Review Article
Authors : Alamgir MA
Keywords : Pre- hypertension; Lifestyle modification
Cardiovascular
disease risk increases throughout the increased range of blood pressure,
including ranges previously considered normal. For example, the person with
systolic blood pressure (SBP) of 135 mm/hg has double risk to encounter the
coronary heart diseases and stroke than those associated with SBP of 115 mm Hg.
Guidelines describe that BP in range of 120-130/80 mmHg is not normal
particularly if associated with risk factors and it is termed as pre-
hypertension, necessitating screening /identification along with approaches of
lifestyle modification.
American Heart
Association has recently estimated that nearly 108 million or 45% adults in USA
has raised blood pressure {BP) and among half of them have uncontrolled
hypertension despite treatment [1, 2]. 59 million people living in USA has
prehypertension with BP in range of 120-130/80 mm/hg. Pre-hypertension
(pre-HTN) is considered as warning sign as mostly it is precursor and leads to
hypertension. Elevated blood pressure has always been a threat and modifiable
cause of cardiovascular mortality and morbidity worldwide. In 2018,
hypertension claimed about half a million deaths as primary or secondary cause.
When considering global figures by the 2020 ISH Global Hypertension Committee,
1.39 billion people had raised blood pressure worldwide, claiming for 10.4 million
deaths per year particularly in middle- and lower-income countries [3].
Generally, the high mortality is due to fact that raised blood pressure is
asymptomatic and population at large is unaware about its complications.
Also, there is
illiteracy and lack of well-coordinated approach for control of blood pressure
among population of south Asians and other under develop countries [4]. The
American and European guidelines have different approach to definitions of
prehypertension, hypertension and their treatment thresholds. The old adage,
formerly regarded as 140/80 mmHg as normal cut off value, no longer rings true.
2017 American College of Cardiology/American Heart Association (ACC/AHA)
guidelines explain new measurements for blood pressure (BP) and categorized
normal BP as value <120/80 mmHg, raised as >120-129/ 80mmHg, stage 1
hypertension as systolic blood pressure (SBP) 130-139 mmHg and/or diastolic BP
(DBP) 80-89 mmHg. Stage 2 hypertension is defined as SBP??140 mmHg and/or
DBP???90 mm Hg [5]. The medical literature says that SBP increases and DBP
decreases until 5th decade, after that DBP decreases and pulse pressure
increases. These changes are link to development of atherosclerosis and related
cardiometabolic risk factors. In presence of diabetes, obesity and
dyslipidemias, the pathological process of atherosclerosis begins even during
normal BP range. There are increased cardiovascular consequences and all-cause
mortality in hypertensives patients with risk factors and recommended to keep
threshold level of 120 mmHg and level above this is well defined disease entity
called as prehypertension.
Pre-hypertension
(pre-HTN) is an epidemic and poses significant public health challenge for both
developed and low- middle income countries. The Sprint Trial was first large
prospective randomized trial and concluded that intensive BP control with
target <120/80mm/Hg was more beneficial in terms of reducing cardiovascular
mortality and morbidity compared with routine BP control to 140 mm Hg [6]. The
landmark Framingham trial revealed some alarming results that 45 percent of
cardiovascular (CV) events like coronary heart disease and stroke occurred at
systolic BP less than 140 mm/Hg [7]. First time, the 7th report of JNC guidelines
coined the term as prehypertension (pre-HPT). With blood pressure >120/80
mmHg and narrated that if values are below this threshold, then the big answer
is the “GOOD” [8]. The reported overall worldwide prevalence of
pre-hypertension is 31% to 50 percent [9, 10]. During this stage, population at
large may have unhealthy lifestyle and do not adopt preventive measures because
they are ignorant and unaware to this well-defined disease entity of pre-HTN.
It is frequently observed that behavioral risk factors among these groups are
physical inactivity, high calorie diet, smoking, binge alcohol drinks and fewer
intakes of fruits with vegetables [11]. It means primary preventive strategies
should be accomplished in general population and particularly for the
population at risk. An important fate of pre-HPT for population is the
development of hypertension [12]. Based upon these facts, the aim of our review
is to sort out retrospectively the recent evidence-based research about pre-HTN
and update some preventive approaches along with lifestyle modifications.
As mentioned earlier,
80 to 90 percent participant in Framingham trial had at least one additional CV
risk factor. Considering the drug treatment of maintaining target BP value
<120/80 mm Hg, some controversial results were obtained in ACCORD trial of
diabetic patients. Treating BP to less than 130 mm Hg only with drugs, resulted
in serious adverse effects in term of heart, kidney and retinal diseases except
stroke [14]. It is degree or duration of risk factors along with level of BP
that strongly influence CV outcome. So, goal of therapy should be to reduce
modifiable risk factors as well. Research shows that with SBP as low as 90
mm/Hg, the CV events increase with step wise increase in BP and this effect is
potentiated many folds with associated risk factors [15]. Canadian yearly
guidelines had more emphasis on lifestyle modification and in this situation
pharmacological treatment is recommended when having “UGLY” macro vascular
complications as well. Generally, drug treatment is recommended in addition to
lifestyle modification when SBP>160 or DBP >100 mmHg [16]. These
prescribers urge to keep BP below 120/80 mmHg. Keeping in view about above
mentioned theme, large NIHR-sponsored UK trial compared mortality and risk of
cardiovascular events among patients with or without antihypertensive drugs.
They don’t support recommendations of US (ACC/AHA) clinical guidelines for the
initiation of treatment in low-risk patients with mild hypertension [17]. It is
worth mentioning for younger age population that while addressing high normal
or pre-hypertension, it is needed to manage associated risk factors rather than
drug therapy.
To be healer is a
privilege. Physician has divine gift of knowledge, skill and can be a role
model in the society by educating patients for maintaining healthy lifestyle
and preventing complications. It should be reminded that in stage 1
hypertension, 6 months or one-year lifestyle modification plan must be
attempted before drug therapy [18]. As way of life changes, it requires strict
adherence to combat risk factors. Below
is mentioned the updated outlines of essential steps and recent evidence-based
recommendations in these regards.
Correlation of
pre-HTN and HTN has been extensively studied and simple weight reduction is
tremendously rewarding in reducing BP in pre-HTN. Study shows that 5% weight
gain was associated with 20-30% increase odd of developing pre-hypertension. Aerobic
exercise, stationary indoor or outdoor road cycling and yoga has proven
benefit. A heart-healthy diet alone or as part of a holistic healthy lifestyle
for hypertension control, weight management, and CVD risk reduction [19].
Expert guidelines recommend 30 minutes brisk walk 6 times per week. More
extensive exercise did not prove to be beneficial. Effective BP lowering is
achieved even without attaining normal BMI.
Various patterns of
lipid abnormalities may be seen. Research had a rational explanation and
elaborated that elevated BP associated with hyperlipidemia, is frequently
resulting with reduced life expectancy. An epidemiological trial showed
significant increase in total cholesterol, LDL, VLDL and serum triglyceride
level in pre- HPT compared to normotensives. While there was no significant
change in HDL level in later group [20]. Trials have shown that the prevalence
of the co-existence of hypertension and dyslipidemia is seen in the range of 15
to 31% and authors have coined the term as ‘lipitension’ [21]. Evidence based
research showed that diabetics commonly have pre HTN or hypertension along with
obesity and dyslipidemia ; constellation of these terms is called as metabolic
syndrome [22]. The literature explained that among diabetics, development of
atherosclerosis and HTN is accelerated due to insulin resistance, leading to
2-4 folds more risk of the atherosclerotic cardiovascular disease (ASCVD)
outcome. Lifestyle modification including heart healthy and Mediterranean diet,
DASH diet plan and moderate exercise have profound beneficial role [23]. Large
epidemiological MRFIT (Multiple Risk Factor Intervention Trial) observed
interplay of lipitension among 356,222 men and followed up for 12 years. Their
results emphasized that it was multiplicative adverse effect in cardiovascular
outcome even with mild elevated levels of both hypertension and lipoproteins
[24]. Furthermore, the Framingham study results also reflected that moderate
hypertension and hyperlipidaemia had a similar 10-year risk of coronary heart
disease as those with highly elevated systolic BP or LDL cholesterol alone. The
preventive measures discussed in this paper has beneficial effects along with
drugs if needed.
Dietary
Administration to Stop Hypertension or Mediterranean diet has equal outcome as
single drug therapy in HTN. This plan comprises vegetables, plenty of fruits,
dietary fiber, whole grains and less consumption of meat, carbohydrates and
saturated fats. Age and body mass index (BMI) are significant predictors of pre
HTN [25]. Junk food and soft drinks have bad effect. Online Mediterranean diet
plan can be downloaded. Dietary modification along with planned exercise and
weight reduction works synergistically for optimal reduction of high BP.
Fermented Diet: Recently a meta-analysis, including 24 randomized control
trials concluded that supplementation of yogurt and other fermented diet
reduced blood pressure in pre-HTN, but it should be part of other weight
reduction plan [26].
Inactivity most
common identifiable and recognized risk factor and this term needs
understanding. Physical activity means walking, lifting, hauling, shoveling and
carpentry etc. Lack of physical activity is sedentary behavior and means
activities that do not increase energy expenditure above the resting level e.g.
sitting or sleeping, computer use, video gaming and watching television. A
recent met-analysis of 15 randomized controlled trials comparing effect of
exercise and pharmacological therapy for ambulatory BP monitoring concluded
that exercise do have beneficial effect in lowering BP particular as an
adjuvant to other modalities [27]. European guidelines strongly recommend
aerobic exercise for stage 1 pre-HPT and as adjuvant with drug therapy in stage
2 and 3 as well [28].
Although there is
already established relationship of high sodium intake with hypertension, but
there is also recent evidence that dietary salt restriction reduces BP among
normotensives or Pre -HTN [29]. It is true among all ethnic groups with
children and adults. A first meta-analysis of its kind showed dose response
sodium - BP relationship in normotensive /hypertensive papulation and recommend
salt as low as 1 to 2 grams per day [30]. There were over 1.8 million deaths,
and over 44 million disability-adjusted life years lost (ex CVD, stroke), as a
result of excess dietary sodium consumption [31]. It is recommended no added
salt in cooking for high-risk individuals.
Too much booze is
harmful. Most studies have conflicting results but half of all related meta
-analysis conducted so far show that less than 2 oz per day for men and less
than 1 oz per day for women may have independent effect of lowering systolic
blood pressure < 3.5mm Hg [32]. Smoking also has well established
relationship with accelerated atherosclerosis and developing of hypertension.
The only answer in this regard is to “quit smoking plan”
Among afore mentioned
practices, let us consider which is most beneficial?
In a recent valuable meta- analysis, 22
non-pharmacologic intervention were assessed from 60 166 potentially relevant
articles and 120 eligible articles (14 923 participants) with a median
follow-up of 12 weeks. For adults with prehypertension, their evidence
indicated that the Dietary Approach to Stop Hypertension (DASH) was superior to
all other no pharmacologic interventions in lowering systolic and diastolic BP,
compared with usual care. Moderate- to high-quality evidence indicated that
aerobic exercise, low-sodium and high-potassium salt, isometric training and
meditation could lower SBP and DBP as well [33].
Almost all evidence-based
studies and literature favor lifestyle modification in pre-HTN with or without
risk factors; results will be promising by reducing mortality. Health care
providers should transform this knowledge to papulation at large and save human
lives because “Thousands of hands are waiting to build your home in heaven.”
I hereby dedicate this paper to my late parents, Muhammad
Aslam Khan and Kaneez Zineb, owing to their affectionate parenting, education
and benevolence for me. God bless them ever.