| Hypertension,
known as the "silent killer" since it shows few, if
any, symptoms, is a major risk factor for other cardiovascular
diseases such as stroke, heart attacks and congestive
heart failure.
Defined as a systolic blood pressure greater than
or equal to 140mmHg and a diastolic blood pressure
of greater than or equal to 90mmHg, hypertension is
the most prevalent of all cardiovascular diseases
in the developed world. In fact, some 20-30% of adults
in developed countries have high blood pressure.
Hypertension is classed into two types: primary and
secondary. Primary hypertension, for which there is
no known cause, affects 95% of all hypertensive patients
and is also known as essential hypertension.
Secondary hypertension, on the other hand, is a result
of other diseases including kidney diseases, Cushing's
syndrome, adrenal gland tumours, and Wilm's tumour
to name a few, or it may be caused by treatment with
medications, including oestrogen-containing contraceptives.
Secondary hypertension also complicates 10% of all
pregnancies.
Disease
prevalence
Blood pressure increases with age, particularly after
55 years, and is slightly more common in men than
women. A survey conducted by the National High Blood
Pressure Education Program in the United States, the
National Health and Nutrition Examination Survey (NHANES),
estimated that some 50 million Americans have high
blood pressure.
Hypertension is also more common in people who are
overweight
and physically inactive and in those who smoke,
drink excess alcohol and have a diet high in fat or
salt. High blood pressure is also common in diabetics.
As the population
ages, the prevalence of hypertension increases.
In industrialised societies, high stress jobs, a lack
of physical activity and the unlimited availability
of fast foods rich in fats and salts, but of little
nutritional value, all contribute to the rising prevalence
of hypertension seen in recent years.
With the highest intake of salt per capita in the
world, the incidence of essential hypertension is
highest in Japan, which accounts for 54% of the prescriptions
written for hypertension out of the ten countries
surveyed.
According to IMS HEALTH's new service Diametrics,
the highest number of prescriptions written peaks
in the 70-74 years age group, with women accounting
for 58% of prescriptions written. In men, the highest
number of prescriptions written peaks slightly earlier
in the 65-69 years age group, with men accounting
for 45% of prescriptions written for this age group.
Hypertension
Market Age and Sex Profile
|
Source
Diametrics
Looking at market dynamics, Japan has shown steady
double-digit or high single-digit growth in terms
of prescriptions written over the last four years.
Canada and Spain have also shown double-digit growth
rates in prescriptions written during the same period.
In contrast, the US has shown just low-to-medium single-digit
growth in prescription terms over this period.
While it cannot be cured, essential hypertension can
be effectively managed with appropriate treatment.
New guidelines on the management of hypertension published
by The International Society of Hypertension (ISH)
in collaboration with the World Health Organisation
(WHO) stipulated that the goal of treatment is to
restore blood pressure to normal or optimal levels
and to address other risk factors. Lifestyle changes
such as reducing weight, stopping smoking, dietary
changes, taking more exercise and limiting alcohol
consumption can lower blood pressure, but in patients
at high risk and with blood pressure remaining high
despite these changes, antihypertensive drugs are
the treatment of choice.
Older treatments still feature strongly in prescriptions
written
According to Diametrics the main classes of medications
for hypertension are calcium antagonists, angiotensin-converting
enzyme (ACE) inhibitors, beta-blockers, angiotensin
II antagonists and thiazide diuretics.
The choice of medication is dependent on the individual's
characteristics.
Hypertension
Market by Therapeutic Category
by
Market Value
Hypertension
Market by Prescriptions Written
|
Source
Diametrics
In the new IMS HEALTH report, ACE inhibitors, such
as AstraZeneca's Zestril (lisinopril) and Merck &
Co's Vasotec (enalapril), account for 19% of the prescriptions
written for hypertension. The 16-year Glasgow Blood
Pressure Clinic Study showed that ACE inhibitors improve
survival and reduce all-cause mortality by 25% in
hypertensive patients. The side effect of dry cough
is the main drawback of this class of compounds.
Prescriptions for calcium antagonists such as Pfizer's
Norvasc (amlodipine) and Aventis' Cardizem CD (diltiazem)
remain high, accounting for 31% of prescriptions written,
although amongst the medical profession they are losing
their appeal. In the Glasgow study, calcium antagonists
increased mortality by coronary artery disease and
vascular disease by 60% and 50% in hypertensive patients.
Diuretics such as hydrochlorothiazide and Aventis'
Lasix (furosemide), and beta-blockers such as AstraZeneca's
Tenormin (atenolol), each account for 11% of prescriptions
for hypertension.
New classes are gaining ground
Angiotensin II antagonists are relatively new to the
market, the first products being launched in the mid-1990s,
and now account for just over 4% of prescriptions.
As therapy for hypertension, they are highly regarded.
Unlike the ACE inhibitors, they do not induce a dry
cough and as a result are prescribed when ACE inhibitors
are not tolerated. Important drugs in this class are
losartan, valsartan, irbesartan and candesartan cilexetil.
IMS HEALTH's new Diametrics
service provides an analysis of sales and prescription
data for a disease together with drug and patent data,
giving a comprehensive picture of key diagnoses. Diametrics
is available for a number of diseases, including:
- Congestive
Heart Failure
-
Hyperlipidaemia
-
Hypertension
-
Obesity
-
Stroke
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