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C HAPTER 35 / Hypertension 805

coat effect and is defined as the difference between the office
Table 35-3 ■ TRENDS IN AWARENESS, TREATMENT, AND and daytime ambulatory BP; it is present in the majority of hy-
CONTROL AMONG PARTICIPANTS WITH HYPERTENSION pertensive patients. Its magnitude can be reduced (but not
IN THE U.S. POPULATION, 1999 TO 2004 eliminated) by the use of stationary oscillometric devices that
automatically determine and analyze a series of BPs over 15 to
National Health and Nutrition Examination
Survey (%) 20 minutes with the patient in a quiet environment in the of-
fice or clinic.
1999–2000 2001–2002 2003–2004
Masked HTN or Isolated Ambulatory HTN. The con-
Awareness 69 71 76 verse condition of normal BP in the office and elevated BPs else-
Treatment 58 60 65 where, such as at work or at home is somewhat less frequent than
Control † 29 33 37 white coat HTN but more problematic to detect. 66 Lifestyle can
contribute to this, for example, alcohol, tobacco, and caffeine
† Among all with hypertension consumption and physical activity away from the clinic or office.
From Ong, K. L., Cheung, B., Man, Y. B., et al. (2007). Prevalence, awareness, treat-
ment, and control of hypertension among United States adults 1999–2004. Hyperten-
9
9
sion, 49, 69–75. Clinical Evaluation
The objectives of the medical assessment for HTN are to deter-
mine (1) diagnosis and stage of HTN, (2) secondary causes of
HTN, (3) presence of TOD, (4) level of global CVD risk, and (5)
the plan for individualized monitoring and therapy. The assess-
to morbid events is the average level, although there is also ac- ment should include a thorough history and physical examination,
cumulating evidence that suggests that hypertensive patients including orthostatic BP change. Display 35-3 lists many of the
whose BP remains high at night (nondippers) are at greater risk important variables to assess during the history and physical exam-
for cardiovascular morbidity than dippers. 67 Less data are avail- ination. It is also important to ask the patient about any nontra-
69
able to define the clinical significance of BP variability, although ditional remedies they may be using including herbs, vitamins, and
it has been suggested that it is a risk factor for cardiovascular other supplements. Display 35-4 lists the basic and optional labo-
morbidity. ratory tests recommended by the Joint National Committee on
The recognition of these limitations of the traditional clinic Prevention, Detection and Treatment of Hypertension (JNC 7) for
readings has led to two parallel developments: first, increasing use the assessment of TOD.
of measurements made out of the clinic, which avoids the unrep- Secondary HTN, a potentially curable condition, occurs in an
resentative nature of the clinic setting and also allows for increased estimated 5% to 10% of HTN cases; therefore, clinicians should
numbers of readings to be taken; and second, the increased use of evaluate for secondary causes (see Display 35-1). Additional eval-
35
automated devices, which are being used both in and out of the uation is recommended in patients whose age, severity of HTN,
office setting. 66,68 It is increasingly recognized that office meas- medical history, physical examination, or laboratory findings are
urements correlate poorly with BP measured in other settings and suggestive of secondary HTN. Poor response to antihypertensive
that they can be supplemented by self-measured readings taken drug therapy or an accelerated phase of previously well-controlled
with validated devices at home. There is increasing evidence that HTN also indicates a need for further investigation. 7
home readings predict cardiovascular events and are particularly
useful for monitoring the effects of treatment.
Prognosis
Home BP Monitoring. Home BP monitoring overcomes
many of the limitations of traditional office BP measurement and In the vast majority of cases, HTN cannot be cured. The rela-
is both cheaper and easier to perform than ambulatory BP moni- tionship between BP and risk of CVD events is continuous, con-
7
toring. Monitors using the oscillometric method are currently sistent, and independent of other risk factors. For individuals
available and are accurate, reliable, easy to use, and relatively in- aged 40 to 70 years, each increment of 20 mm Hg in SBP or
expensive. An increasing number of individuals are using them 10 mm Hg in DBP doubles the risk of CVD across the entire BP
5
regularly to check their BP at home. Home BP monitoring has range from 115/75 to 185/115 mm Hg. The effectiveness of
been endorsed by national and international guidelines and the lifestyle and pharmacologic treatment in reducing BP has been
American Heart Association recently provided detailed recom- demonstrated and substantial evidence indicates that controlling
mendations for their use. 68 Home BP monitoring has the poten- BP in hypertensive patients significantly lowers risk of CV mor-
5,70–72
tial to improve the quality of care while reducing costs. bidity and mortality. A small reduction in BP could
markedly reduce the risk of heart failure, stroke, and myocardial
White Coat HTN. Approximately 15% to 20% of people infarction. 7,73 The recent improvements in HTN control rates
with stage 1 HTN have persistently elevated BP in the presence and decreased mean BPs, especially among the older adults, may
of a health care worker, particularly a physician. However, when help to decrease the incidence of strokes and heart attacks, which
BP is measured elsewhere, including at work, BP is not elevated. is highly encouraging. 3
When this phenomenon is detected in patients not taking med-
ications, it is referred to as white coat HTN. The commonly Prevention
used definition is a persistently elevated average office BP of
140/90 mm Hg and an average awake ambulatory reading of The prevention of HTN is a major public health challenge. Many
135/85 mm Hg. 66 Although it can occur at any age, it is more cases of HTN, cardiovascular and renal disease, and stroke might
common in older men and women. The phenomenon responsi- be prevented if the rise in BP with age could be prevented or di-
7
ble for white coat HTN is commonly referred to as the white minished. The six interventions that have been shown to delay or