Epidemiology of Hypertension

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Epidemiology of Hypertension
Stanley S. Franklin, MD, FACP, FACC Clinical
Professor of Medicine University of California at
Irvine Associate Medical Director UCI Heart
Disease Prevention Program Irvine, California
2
Agenda epidemiology of hypertension

• BP measurement
• Defining hypertension
• Why an important public health problem
• Intervention trials and meta-analyses
• Management strategies
• Barriers to treatment
• Prevention strategies

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How to measure blood pressure?
4
Ascultatory method of blood pressure measurement
Nokolai Korotkoff, 1905
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Noninvasive Blood Pressure Measurement

• Methodologies
• Auscultatory (K sound)
• - Mercury
• - Aneroid
• - Oscillometric
• Locations Situations
• - Upper arm - Clinic
• - Wrist - Home
• - Finger - Ambulatory

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Defining Hypertension By the numbers? 95
DBP 160/95 140/90 130/85 gt120/80 A number at
which the benefits of intervention exceed those
of inaction
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CV Mortality Risk Doubles withEach 20/10 mm Hg
BP Increment
8
7
6
5
CVmortalityrisk
4
3
2
1
0
115/75
135/85
155/95
175/105
SBP/DBP (mm Hg)
Individuals aged 40-70 years, starting at BP
115/75 mm Hg. CV, cardiovascular SBP, systolic
blood pressure DBP, diastolic blood
pressure Lewington S, et al. Lancet. 2002
601903-1913. JNC 7. JAMA. 20032892560-2572.
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JNC Reclassification of BP Based on Risk
JNC VI
JNC 7
DBP (mm Hg)
SBP (mm Hg)
DBP (mm Hg)
SBP (mm Hg)
Category
Category
Source for JNC VI Arch Intern Med.
19971572413-2446. Adapted with permission from
Chobanian AV et al. Hypertension.
2003421206-1252.
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Prevalence of Blood Pressure Categories in US
Adults 20 Years of Age (NHANES 1999-2000)
Greenland, Croft, Mensah (CDC). Arch Intern Med.
20041642113f
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Prehypertension

• Is not a disease,
• Is not hypertension,
• Is not an indication for drug treatment of HTN,
• Does not have a BP goal,
• Does predict a higher risk for developing CV
  events,
• Does predict a higher risk for developing HTN,
• Should be an incentive to improve lifestyle
  practices for prevention of HTN and CVD.

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Defining Hypertension By hemodynamic
mechanism? Increased peripheral vascular
resistance versus Increased large artery
stiffness
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The Arterial Pulse Wave
Pulse pressure
1/3 SBP 2/3 DBP
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Hemodynamic Components of BP

• MAP - STEADY COMPONENT (due to CO and SVR)

PP PULSATILE COMPONENT (due to LV ejection
and elastic artery stiffness)
SBP rises with increased resistance and
stiffness DBP rises with increased resistance
and decreases with increased
stiffness
Elzinga G, Westerhof N. Circ Res
197332178-186. Yano, et al. Basic Res Cardiol
199792115-122. Berne
RM, Levy MN. Cardiovascular Physiology
1992135-151.
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Defining Hypertension By subtype? IDH, SDH, ISH
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Patterns of Arterial Pressure Change With Aging
PP
SBP
Change mm Hg
MAP
DBP
30-35
35-40
40-45
45-50
50-55
55-60
60-65
70-75
65-70
Age (yr)
Franklin SS et al. Circulation. 199796308-315.
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Distribution of Hypertension Subtype in the
Untreated Hypertensive Population by Age (NHANES
III)

Diastolic Hypertension
17
16
16
20
20
11
Frequency of hypertension subtypes in all
untreated hypertensives ()
lt40
40-49
50-59
60-69
70-79
80
Age (y)
Numbers at top of bars represent the overall
percentage distribution of untreated hypertension
by age. Franklin et al. Hypertension.
200137 869-874.
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An Analysis of NHANES III Blood Pressure Data

• Summary Hypertensives fall into one of two
  categories
• 1. A smaller (26), younger (age ?50 years),
  predominantly male (63) with diastolic
  hypertension out of proportion to systolic
  hypertension (primarily IDH and SDH)
• 2. A larger (74), older (age ?50 years),
  predominantly female (58) with systolic
  hypertension out of proportion to diastolic
  hypertension (primarily ISH).

Franklin et al. Hypertension 200137 869-874
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Multiple Risk Factor Intervention Trial (MRFIT)
Effect of BP on CHD-Related Mortality
(N316,099)
Death Rateper 10,000Person-Years
?160
140-159
?100
90-99
80-89
120-139
SBP (mm Hg)
DBP (mm Hg)
75-79
70-74
lt120
lt70
Men aged 35-57 y followed for a mean of 12
y. Neaton JD, Wentworth D. Arch Intern Med.
199215256-64.
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Why is hypertension considered a major Public
health problem in the United States?
Firstly, hypertension is very common In the
adult population
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Increased Prevalence of Hypertension in the
United States from 1988-1994 (NHANES III) to
1999-2000 NHANES
30 increase, plt.001
Population With Hypertension (millions)
Nearly 1 in 3 Adults (31) in the US Has
Hypertension
Fields, et al. Hypertension. 200444398f
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Age Distribution of Hypertensives in US
Population NHANES III and the 1991 Census
26
74
23.7
47.4 million hypertensives 26.0 of US population
21.3
19.2
Hypertensives Within Age Group ()
13
9.5
9.6
3.7
Age Groups (y)
Franklin SS. J Hypertension. 199917(suppl
5)S29-S36.
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1976-98 Cumulative Incidence of HTN in Women and
Men Aged 65 Years
Risk of Hypertension
Years of Follow-up
Vasan, et al. JAMA.20022871003
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Trends in Prevalence of Hypertension in the US
Population, by Race/Ethnicity,1988-2000





plt0.01, plt0.001,compared to Non-Hispanic
Whites within given time period no significant
trends across time periods within gender
analyses are age-adjusted to 2000 US population.
Data from Hajjar I, Kotchen TA. Trends in
prevalence, awareness, treatment, and control of
hypertension in the United States, 1988-2000.
JAMA 2003 290 199-206.
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Hypertension Prevalence and Treatment Among
Persons 35-64 Years Old in 6 European Countries,
Canada, and the United States




Based on surveys of 1823 to 23129 respondents
conducted from 1986 to 1999 (US NHANES III survey
data from 1988-1994). Adapted from
Wolf-Maier K et al. Hypertension prevalence and
blood pressure levels in 6 European countries,
Canada, and the United States. JAMA 2003 289
2363-2369.
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Secondly, hypertension is associated with
considerable cardiovascular risk.
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Global Mortality 2000 Impact of Hypertension and
Other Health Risk Factors
High blood pressure
Tobacco
High cholesterol
Underweight
Unsafe sex
High BMI
Physical inactivity
Alcohol
Indoor smoke from solid fuels
Iron deficiency
0
8000
7000
6000
5000
4000
3000
2000
1000
Attributable Mortality (In thousands total
55,861,000)
Ezzati et al. Lancet. 20023601347-1360.
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Defining Hypertension Is it a true risk factor
or a risk marker? A true risk factor is
suspected of being causative of the disease
process. A risk marker is associated with the
disease process without being in the causal
pathway.
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Complications of Hypertension
Hypertension is a risk factor
TIA transient ischemic attack LVH left
ventricular hypertrophy CHD coronary heart
disease HF heart failure.Cushman WC. J Clin
Hypertens. 20035(Suppl)14-22.
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Risk Factor Clustering With Hypertension
30
Men
25
Women
27
26
25
24
20
22
RiskFactors()
20
19
17
15
10
12
8
5
0
0
1
2
3
4
Number of Risk Factors
Risk factor clustering with hypertension, ages
1874 years. Framingham offspring.
Kannel WB. Am J Hypertens. 2000.
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BP is a risk marker for The Metabolic Syndrome
NCEP-ATP III Definition 3 of the Following
Diagnosis is established when 3 of these risk
factors are present.Expert Panel on Detection,
Evaluation, and Treatment of High Blood
Cholesterol in Adults. JAMA. 20012852486-2497.
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Other CVD Risk Factors JNC 7

• Physical inactivity
• Cigarette smoking
• Age (older than 55 for men, 65 for women)
• Family history of premature CVD
• (men under age 55 or women under age 65)

Components of the metabolic syndrome in blue
Chobanian et al. JAMA. 20032892560-2572
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Diabesity
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Framingham Heart Study (1983)
CV Risk Profile
703
700
600
500
459
400
8 Year Probability Per 1,000
326
300
210
200
100
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Systolic BPCholesterolGlucose
Intol.Cigaretes ECG-LVH

• gtgtgt 185
• 185
• 0
• 0
• 0

• gtgtgt 185
• 335
• 0
• 0
• 0

• gtgtgt 185
• 335
• 0
• 0

• gtgtgt 185
• 335
• 0

• gtgtgt 185
• 335

Kannel, 1983
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ATP-III Framingham Point ScoresEstimate of
10-Year Risk for Men
1
5
3
Age Age Age Age Age 20-39 40-49 50-59 60-69 70-7
9
Age, y Points
Systolic BP If If mm Hg Untreated Treated
20-34 -9 35-39 -4 40-44 0 45-49 3 50-54 6 55-59 8
60-64 10 65-69 11 70-74 12 75-79 13
lt120 0 0 120-129 0 1 130-139 1 2 140-159 1 2
?160 2 3
Nonsmoker 0 0 0 0 0Smoker 8 5 3 1 1
6
Point Total 10-Year Risk,
lt0 lt1 0 1 1 1 2 1 3 1 4 1 5 2 6 2 7 3 8
4 9 5 10 6 11 8 12 10 13 12 14 16 15 20 16
25 ?17 ?30
4
HDL mg/dL Points
?60 -1 50-59 0 40-49 1 lt40 2
2
Total Age Age Age Age Age Cholesterol 20-39 40-4
9 50-59 60-69 70-79
lt160 0 0 0 0 0 160-199 4 3 2 1 0 200-239 7 5 1
3 0 240-279 9 6 4 2 1 ?280 11 8 5 3 1
Expert Panel on Detection, Evaluation, and
Treatment of High Blood Cholesterol in Adults.
JAMA. 20012852486-2497.
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Thirdly, there is considerable reduction in
cardiovascular risk with effective lowering of
blood pressure with therapy.
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Long-Term Antihypertensive Therapy Significantly
Reduces CV Events
Stroke
Heart failure
Myocardial
infarction
0
10
20
Average reduction in events ()
20-25
30
40
35-40
50
gt50
60
Blood Pressure Lowering Treatment Trialists
Collaboration. Lancet. 20003551955-1964.
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Fourthly, there is insufficient awareness,
treatment and control of hypertension.
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Hypertension Awareness, Treatment, and Control
US 1976 to 2000
73
70
68
Awareness
59
55
54
51
34
31
Adults
29
27
Treated
10
Control
NHANES III (Phase 2) 1991-1994
NHANES II 1976-1980
NHANES III (Phase 1) 1988-1991
NHANES 1999-2000
Chobanian et al. JAMA. 20032892560-2572.
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Awareness, Treatment, and Control of Hypertension
by Various Populations
80 70 60 50 40 30 20 10 0
73.9
Non-Hispanic Whites Non-Hispanic Blacks Mexican
Americans
69.5
63.0
60.1
57.8
55.6
44.6
44.0
40.3
Prevalence ()
33.4
28.1
17.7
Awareness
Treatment
Control, All Treated
Control, All Hypertensive
Plt.01 Plt.001 Plt.05 (for the difference among
groups within the same survey phase
non-Hispanic whites as the referent for
race/ethnicity). Includes all survey
participants with hypertension, whether treated
or not. Source National Health and Nutrition
Examination Survey 1999-2000 data. Data are
weighted to the US population. Hajjar I, Kotchen
TA. JAMA. 2003290199-206.
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Treated hypertensive subjects with BP lt140/90 mmHg
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Management of Hypertension
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• Hypertension may be an important compensatory
  mechanism which should not be tampered with, even
  were it certain that we could control it.

Paul Dudley White, 1931 Textbook of Cardiology.
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Trials meta-analyses What we do not know
(...and maybe will never know)

• Trial duration is lt10 years treatment benefits
  should be considered in the very long term
  (decades).
• Drop-in effect (subjects under placebo are given
  active drug) and drop-out effect (drop-outs in
  the active treatment group.
• Subjects included in the trials are generally
  healthier than those treated in the clinical
  practice (selection of low-risk subjects).
• Secondary end-points subgroup analyses
  difficult to interperet.

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Clinical Trials in Hypertension
Should we treat ISH in older persons?
What is the best way to treat HBP?
Should we treat DBP in older persons?
What is the goal of treatment?
Can we prevent hypertension?
Should we treat diastolic HBP?
1960s 1970s 1980s 1990-1995 1996-1999 2000 2001-2
003 2004-2008
TROPHY
HR Black, 2003.
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Hypertension Intervention Trials 1959-1970
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SHEP TrialDesign

• N 4736 43 male
• Age gt60
• BP SBP 160-219 and DBP lt90
• Design Placebo control, double blind
• Active Rx Chlorthalidone (atenolol as step 2)
• SBP difference 12 mm Hg
• Duration 4.5 years

JAMA 19912653255
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Systolic Hypertension in the Elderly The SHEP
Trial
JAMA 19912653255
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HYVETElderly, age 80 yrs. treatment drugs vs
placebo
Per Protocol
Beckett N. N Engl J Med. 2008358 epub. March
31, 2008.
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BP-Lowering Treatment TrialistsComparisons of
Different Active Treatments
BP Difference(mm Hg)
Relative Risk
RR (95 CI)
Major CV events
CV mortality
Total mortality
FavorsFirst Listed
FavorsSecond Listed
0.5
1.0
2.0
Blood Pressure Lowering Treatment Trialists
Collaboration. Lancet. 20033621527-1535.
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Seventh Report of the Joint National Committee
onPrevention, Detection, Evaluation, and
Treatment of High Blood Pressure (JNC 7)
EXPRESS
National Heart, Lung, andBlood
Institute National High Blood PressureEducation
Program
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JNC 7 Appropriate BP Targets

• For both CVD and kidney disease, systolic BP is
  far more important than diastolic BP
• Systolic BP should be lt140 mm Hg in all patients,
  and ideally between 120-130 mm Hg in patients
  with complications (diabetes, heart failure,
  kidney disease)
• Only a small fraction of hypertensives are
  achieving appropriate BP control
• Multiple antihypertensive agents are needed for
  most patients
• Those with SBP 120139 mmHg or DBP 8089 mmHg
  should be considered pre-hypertensive who require
  health-promoting lifestyle modifications to
  prevent CVD.

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JNC 7 Considerations for olderpersons with
hypertension

• This population has the lowest rates of BP
  control and the
• greatest absolute benefit with effective
  therapy.
• Lower initial drug doses may be indicated to
  avoid symptoms standard doses and multiple drugs
  will be needed to reach BP targets.
• More than two-thirds of people over 65 have HTN,
  i.e. ISH
• (Isolated systolic hypertension).
  

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JNC 7 Considerations for special populations
with hypertension

• Treatment generally similar for all demographic
  groups
• Socioeconomic factors and lifestyle important
  barriers to BP control
• Prevalence, severity of hypertension increased
  in blacks

JNC 7. JAMA. 20032892560-2672.
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Lifestyle Interventions for Prevention or
Treatment of Hypertension

• Intervention
• Exercise
• Weight reduction
• Alcohol intake reduction
• Sodium intake reduction
• DASH diet

• Blood Pressure Effect
• 5-10 mm Hg (gt30 min gt3x/wk)
• 1-2 mm Hg/Kg?
• 1 mm Hg/drink/d?
• 1-3 mm Hg/40 mmol/d?
• 3-10 mm Hg ?

Adapted from Cushman et al. Endocrine Practice
19973106 Sacks, et al. NEJM 20013343
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Lifestyle Treatment Measures

• Nonpharmacologic treatments are used for
• ? Lowering blood pressure
• Reducing need for antihypertensive agents
• Minimizing associated risk factors
• ? Primary prevention of hypertension

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JNC 7 Algorithm for Treatment of Hypertension
Lifestyle Modifications
Not at Goal Blood Pressure (lt140/90 mm Hg)
(lt130/80 mm Hg for those with diabetes or
chronic kidney disease)
Initial Drug Choices
Chobanian et al. JAMA. 20032892560-2572.
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Number of Medications to Achieve Goal BP in 5
Trials of DM /or Renal Disease
Bakris. J Clin Hypertens 19991141-7
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Barriers to Controlling Hypertension
Patients
Providers
HealthcareSystem
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The Initial Confrontation of the HTN Problem

• Upon making a diagnosis of HTN, tell patient the
  BP reading and what it should be (provide a
  written copy).
• Prepare patient for the probable necessity for
  polypharmacy to control BP with a minimum of
  side effects
• Advise Home BP measurement (135/85 mmHg is
  considered to be hypertensive).

Table 28. JNC 7 Report. Hypertension.
200342(6)1240.
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Self-Measurement of BP

• Provides information useful for
• assessing response to antihypertensive Rx
• improving adherence with therapy
• evaluating white-coat HTN
• Home BP is more strongly related to target organ
  damage and has better prognostic accuracy than
  office BP.

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Defining Hypertension By a Prevention
Strategy General Population Strategy Versus Targ
eted Intensive Strategy
66
Whelton, PK, He J, Appel LA et al., JAMA
20022881882-1888
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Understanding hypertensive CV Risk

• Epidemiology Summary
• Increasing prevalence world wide problem
• Blood pressure as a moving target
• ? PVR in the young, ? stiffness in the elderly
• Predominantly isolated systolic hypertension
• Consider special populations at increased risk
• Hypertension as a part of absolute global CV risk
• Population vs. high risk approaches for prevention