Hypertension Journal

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Prehypertension: What to Do?
  JOHTN
EARLIER STAGE OF HYPERTENSION
Prehypertension: What to Do?
Arvind K Pancholia
Head
Department of Medicine and Preventive Cardiology, ArihantHospital & Research Centre, Indore, Madhya Pradesh, India
Correspondence Author: Arvind K Pancholia, Head, Departmentof Medicine and Preventive Cardiology, Arihant Hospital &Research Centre, Indore, Madhya Pradesh, India
Phone: +919827027920e-mail: drpancholia@gmail.com
 
ABSTRACT
Prehypertension (PHTN) is a global health problem that carriesthe risk of being prone to developing hypertension in the futurealong with double the risk of cardiovascular disease (CVD). Itsprevalence is 25 to 50% based on data from different countries,and it varies with age, sex, birth weight, and body mass index(BMI). Regarding its pathophysiology, several mechanismshave been proposed, but the most validated are Ras activation,oxidative stress, inflammatory cytokines, sympathetic overdrive,and central nervous system activation. Therapeutic lifestylechanges are the foundation for all therapies in prehypertensivepatients, which are recommended by almost all guidelines.Drug therapy has also been tried in a couple of trials and isrecommended in high-risk patients.
Keywords: Dietary approaches to stop hypertension diet,Hypertension, Sodium
How to cite this article: Pancholia AK. Prehypertension: Whatto Do? Hypertens J 2017;3(2):67-71.
Source of support: Nil
Conflict of interest: None
 
 

INTRODUCTION

In 1939, Robinson and Brucer suggested the value ofclinically overt hypertension when the levels are 120 to139 mm Hg (systolic) and 80 to 89 mm Hg (diastolic).1Three decades later, it was termed as "borderline hypertension";2 then in 1997, it was changed to "high-normalblood pressure (BP)."3 The term "PHTN" was coined in2003 by the seventh report of the Joint National Committeeon Prevention, Detection, Evaluation, and Treatmentof High Blood Pressure (JNC7).1 This report intended toidentify those individuals in whom early intervention byhealthy lifestyles could reduce BP and the rate of convertingfrom PHTN to hypertension. The PHTN precedesclinical hypertension and is associated with increasedincidence of CVD.2-4

DEFINITION

The PHTN is defined as a systolic BP (SBP) of 120 to139 mm Hg and/or a diastolic BP of 80 to 89 mm Hg. Later on, the European Society of Cardiology (ESC) andthe European Society of Hypertension (ESH) bifurcatedit into normal (120-129 systolic and 80-84 diastolic) andhigh-normal (130-139 systolic and 85-89 diastolic). TheESH-ESC committee decided against using the term"PHTN" for several reasons:

 
  • There is no reason to combine the two different groupsbecause the risk of developing hypertension wasdefinitely higher in those with high-normal BP thanin patients with normal BP.
  • The term "PHTN" can create anxiety in many subjectsalong with unnecessary medical visits and tests.
  • Although lifestyle changes are recommended by theJNC7 for all PHTNs, this category is a highly differentiatedone, with the extremes consisting of subjectswith no need of any intervention.

PREVALENCE

The National Health and Nutrition Examination Survey(NHANES), 1999-2000 reported that the overall prevalenceof PHTN was 31% all over the world, which washigher in men than in women.5 A statistical analysis ofdisease-free adult NHANES participants, which wasconducted from 1999 to 2006, found that the overallprevalence of PHTN in disease-free adults was 36.3%.6
Prevalence increases in people with7
  • Diabetes,
  • Microalbuminuria,
  • Chronic kidney disease (CKD),
  • Heavy alcohol consumption, and
  • Overweight/obese.

Prevalence in India

In a study from northern India, the reported prevalenceof PHTN is 44%,8 whereas a study in urban Chennaiindicated a 47% prevalence of PHTN in adults >18 years.9In another study, the reported prevalence is 40% in malesand 3040% in females.10 The statewise prevalence in Indiais shown in Graph 1.

RISK FACTORS
The risk factors are indicated in Table 1.

WHY CARE FOR PHTN

Patients with PHTN are at twice the risk of developinghypertension.11 The PHTN is also associated with increased CVD. According to the Framingham study,there is increased risk of myocardial infarction by 3.5fold and an increased risk of coronary artery disease by1.7 fold11 (Graph 2).

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Arvind K Pancholia

Prehypertension: What to Do?
Graph 1: Statewise prevalence of PHTN in India

Table 1: Risk factors
Prehypertension: What to Do?

Results from the Strong Heart Study12 showed anincreased risk of CV events when PHTN is associated withdiabetes compared with diabetes or PHTN alone (Graph 3).

Prehypertension: What to Do?
Graph 2: PHTN and CV risk (Source: Vasan et al11)

 
The study also showed that 37% of prehypertensiveswill progress to hypertension over the next 4 years.There is a 2-fold increased risk of diabetes also in PHTN.Compared with a normal BP, PHTN is associated witha 27% increase in all causes of death and a 66% increasein cardiovascular deaths.13

Analysis from the CARDIA study suggests that PHTNin early adulthood leads to increased coronary calciumlater in life.14 The PHTN is also associated with increasedcarotid intima thickness.15 There is increase in left ventricular(LV) mass index also with PHTN16 (Graph 4).

It is also associated with increased risk of CKD.17A study also showed the worsening of renal functionby 11 to 91% in prehypertensive individuals. Preexistingdiabetes showed a strong relationship of PHTN andCKD risk. The basic pathophysiology for the developmentof CKD is the greater degree of renal arteriosclerosisand mesangial proliferation in prehypertensives.17High-normal BP is associated with poor cognitive performancealso. The relationship between BP and cognitive performance is linear, even in normotensive and prehypertensiveranges.18 The PHTN also predicts pregnancyinducedhypertension and its postpartum progression.19The PHTN is also linked with metabolic syndrome andCVD (Flow Chart 1).

Prehypertension: What to Do?
Graph 3: Strong heart study (Source: Segura and Ruilope12)

 
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Prehypertension: What to Do?

Prehypertension: What to Do?
Graph 4: PHTN and LV mass index (Source: Mousa et al16)

Table 2: Joint national committee 7 recommendations:Prehypertension lifestyle changes
Prehypertension: What to Do?

PATHOPHYSIOLOGY

Many hypotheses are proposed to explain the underlyingpathophysiology of PHTN.
  • Renin-angiotensin-aldosterone system activation
  • Oxidative stress
  • InflammationSympathetic nervous system activation
  • Central mechanism

PHTN: WHAT TO DO ?

Therapeutic Lifestyle Changes

Practically all the guidelines, previous3 and recent guidelines,20 recommend specific lifestyle modifications for PHTN. The most recent recommendations (JNC7 report)4are as follows:

 
Flow Chart 1: Cardiometabolic syndrome and link with CVD(Source: Expert Rev Cardiovasc Ther 2013)
Prehypertension: What to Do?

Table 3: DASH diet
Prehypertension: What to Do?

  • Maintaining BMI between 18.5 and 24.9 kg/m2; thisis expected to reduce SBP by 5 to 20 mm Hg for each10-kg reduction in weight.
  • Consuming more fruits and vegetables in diet; this isexpected to reduce SBP by 8 to 14 mm Hg.
  • Restricting sodium to no more than 6 gm of table saltper day; this is expected to reduce SBP by 2 to 8 mm Hg
  • Brisk walking for at least 30 minutes per day or regularaerobic physical activity; this is expected to reduceSBP by 4 to 9 mm Hg.
  • Reducing alcohol consumption; this reduces SBP by2 to 4 mm Hg (Table 2).

Dietary Approaches to Stop Hypertension (DASH) dietplan21 (Table 3), which uses a diet rich in fruits, vegetables,legumes, nuts, and low-fat dietary products and low saturatedfats, has a significant lowering of BP. The DASH dietcan reduce BP by 8 to 14 mm Hg, an effect that was augmentedeven further when dietary sodium was restricted. The OmniHeart Collaborative Research Group study22 inwhich the DASH diet was modified to provide more proteinand unsaturated fat and less carbohydrate showed impressivereductions of BP. The Trials of Hypertension Prevention(TOHP) I and TOHP II trials23 (Graph 5) showed thatdietary sodium reduction for 18 months (TOHP 1) or for36 to 48 months (TOHP II) reduces the primary end points(myocardial infarction, stroke, coronary revascularization,or cardiovascular-related death) in middle-aged individualswith PHTN by 25% lower compared with placebo group.The PREMIER trial24 demonstrated that multicomponentbehavioral interventions with and without the DASH dietproduced significant reductions in the 10-year risk of coronaryheart disease in subjects with PHTN.

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Arvind K Pancholia

Prehypertension: What to Do?
Graph 5: Cumulative incidence of CVD by sodium interventiongroup in TOHP I and II (Source: Cook NR et al.23

PHARMACOTHERAPY

The primary approach to treat PHTN is therapeutic lifestylechanges, which have been recommended by severalguidelines. Pharmacotherapy is recommended mainly inhigh-risk groups with CVD and CKD. However, there isstill no consensus. Few trials have been done with differentpharmacological agents with mixed results.

The Trial of Preventing Hypertension (TROPHY) studyevaluated the effect of angiotensin II receptor antagonistcandesartan cilexetil on the prevention of PHTN progressingto stage 1 hypertension25 (Graph 6). After 4 years,stage 1 hypertension developed in two-thirds of patientsin the placebo group, while in the intervention group,there was 66% reduction in the risk of development ofincident hypertension.
 
Prehypertension: What to Do?
Graph 6: TROPHY: Reduction in new-onset hypertension(Source: Julius et al25)

The PHARAO study is the prevention of hypertensionwith the angiotensin-converting enzyme inhibitor Ramiprilin patients with high-normal BP-a prospective, randomized,controlled prevention trial of the German HypertensionLeague.26 The study showed significant reduction inthe risk of progression to manifest hypertension by 34.4%.

The PREVER prevention trial27 is the combination ofchlorthalidone and amiloride in prehypertensive patientsthat effectively reduces the risk of incident hypertensionand beneficially affects LV mass. After 18 months, theincidence of hypertension was 11.7% in the diuretic armvs 19.5% in the placebo arm.

Follow-up of Prehypertensive Patients

Subjects with PHTN need to be treated and evaluated everymonth or two, until the BP goal is reached and then every3 to 6 months thereafter. Subjects with complications/endorgan damage, such as heart or kidney disease may needto be evaluated more frequently at regular intervals.

CONCLUSION
  • Prehypertension is a common problem in thecommunity.
  • Its prevalence is on the rise.
  • It is associated with increased risk of hypertension,target organ damage, and CVD.
  • Healthy lifestyle is the foundation for all therapies inpersons with PHTN.
  • Drug therapies have been tried, but there is noconvincing evidence that antihypertensive therapychanges the course of PHTN.

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Prehypertension: What to Do?

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