E-drug: 1999 WHO-ISH hypertension guidelines
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1999 WHO-ISH guidelines for the management of hypertension are in
contradiction with current clinical evaluation data.
Excessive extrapolations of the data resulting from the HOT study, and the
massive implication of the pharmaceutical industry have already been
largely underlined (among others: Bradbury J. (Lancet 1999 ; 353 : 563) ;
Open letter to Dr Brundtland "HOT: can we turn WHO around?"). Indeed, the
claimed therapeutic objective of lowering the blood pressure below 130/85
cannot be based on the HOT study. In the HOT study, the lowering of the
diastolic blood pressure to 80, 85, 90 or 95 mm Hg did not yield a
difference in terms of cardiovascular morbidity (except in diabetics). Yet
the 1999 WHO-ISH working group has suggested that a difference exist.
Other statements of the 1999 WHO-ISH guidelines are just as disturbing.
The WHO-ISH working group proposes to use as first choice any
anti-hypertensive drug of the six pharmacological groups. This does not
take into account the different risks of adverse effects when drugs are
taken for long duration and/or in particular settings. It overlooks that
diuretics and beta-blockers are the anti-hypertensive drugs with the best
demonstrated effect on cardiovascular morbi-mortality.
In addition, the WHO-ISH working group does not distinguish drugs within a
given pharmacological group. This proposal is questionable, and even
unacceptable for dihydropyridins: clinical trials have shown a higher
incidence of myocardial infarction with dihydropyridins than with ACE
inhibitors in diabetics. Indiscriminate use as first choice of any
anti-hypertensive drug may result in considerably increasing considerably
cost without individual or collective benefit.
The WHO-ISH working group favours fixed drug combinations, although there
is no data from randomized clinical trials to justify this statement.
Hypertension management must be based on the available evidence. The
strategy must use the existing data of clinical evaluation. In April 1999,
"la revue Prescrire" has published recommendations for the management of
high blood pressure based on all relevant clinical trials ("Les traitements
antihypertenseurs" Rev Prescr 1999 ; 19 (194) : 288-296). These proposals
are in agreement with the independent and most recent recommendations (for
example NIH no.98 - 4080, November 1997).
In mild hypertension, uncomplicated and without diabetes, before 65 years,
diuretic and beta-blockers remain the best validated treatments. In a
trial, captopril was a little less effective than a diuretic or a
betablocker for the prevention of stroke. The preventive effect of calcium
channel blockers remains uncertain and several data raise the assumption of
an inferiority of the dihydropyridins to other antihypertensive drugs (less
effective and safe). Clinical trial evaluating the preventive effect of the
other anti-hypertensive drugs is lacking (i.e., central acting-,
alphablockers, angiotensin II inhibitors).
In patients over 65, reduced doses of a diuretic or a beta-blocker yield
significant benefits, but one ought to be cautious about the risk of
postural hypotension.
In type 2 diabetics, ACE inhibitors and beta-blockers are the first choice
treatments; in two trials coronary events were more frequent with a
dihydropyridin than with a ACE inhibitor. The use of dihydropyridins must
be questionned.
It is possible to choose the antihypertensive drug best adapted to
hypertension with complication: diuretic after stroke, beta-blocker after
myocardial infarction, etc.
We do wonder what are the reasons which can lead an international
organization such as WHO to endorse recommendations despite an obvious loss
of control. We also worry about the growing place of drug industry within
WHO, and of an increasingly large number of international organizations and
scientific societies.
J�r�me Sclafer pour La revue Prescrire
<jeromjet@easynet.fr>
La revue Prescrire - BP 459 - 75527 Paris Cedex 11 - France
Tel: +33 (0)1 4700 9445 Fax: +33 (0)1 4252 1582
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