The Nest
N°1 - O CTOBER 1996
Infant Nutrition
Does oral rehydration therapy (ORT)
reduce diarrhea mortality?
Professor R. Bradley SACK, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, USA
The unequivocal, simple
answer is YES ! But that
answer does not adequately address the real
problem, which is the
adequacy and frequency
with which it is used. If
poorly used, there will be
little or no effect; if used
properly there will be a
dramatic effect.
With improvements in the
treatment of acute diarrhea,
the mainstay of which is ORT,
it is estimated that approximately 1 million fewer infants
and children die each year
from diarrhea. This has moved
diarrheal disease from being
the most common cause of
childhood deaths to second
place, being displaced by acute
respiratory infections, primarily pneumonia. However more
than 3 million children still die
from acute diarrheal diseases
each year, so additional
improvements in preventing
mortality are still needed.
I will first summarize the evidence for ORT efficacy (as
studied under controlled conditions) and effectiveness (as
used in the real world), and
then discuss reasons why the
worldwide mortality from
acute diarrhea is still unacceptably high. But first a word
about the terminology. The
terms ORS (oral rehydration
solution(s)) and ORT are
sometimes used interchangeably, but there is a clear
distinction.
ORS refers to the solutions
themselves, of which there are
many. They all include sodium,
chloride, potassium, and a
base (in the form of bicarbonate or citrate) and an actively
absorbed substrate that is
responsible for the absorption
of sodium ions, which are the
critical electrolytes that need
to be replaced to correct and
prevent dehydration. Substrates may be glucose (which
is used most widely), sucrose,
malto-dextrins or cereals
which have been cooked.
These dry ingredients may be
supplied in an inexpensive
packet to be dissolved in a
measured amount of clean
water, or in pre-mixed more
expensive solutions, as in most
developed countries. All solutions must be given appropriately by the care giver to maximize effectiveness.
2
ORT, however, is a much more
inclusive term, and includes
not only the use of ORS, but
also the use of other household fluids (such as soups, porridge, salt-sugar mixtures) and
the provision of early feeding
during the diarrhea episode.
HOW WELL DOES ORT
WORK IN THE HOSPITAL
AND IN THE COMMUNITY?
The very earliest studies (mid1960s) were carried out in the
Indian subcontinent with
cholera, the most severe of all
the acute diarrheal diseases
and the most in need of an
alternative to intravenous fluids, which are expensive and
often unavailable, particularly
in rural areas. All studies
showed that different formulations of ORS, with all of the
substrates tested, were effective clinically in replacing the
losses of fluid and electrolytes
in the stool once clinical shock
had been corrected with initial
intravenous fluids. Thereafter
other dehydrating diarrheas
caused by all known etiologies
(bacteria and viruses) were
studied in all age groups with
similar findings: ORS was uniformly effective in a controlled
clinical setting. Indeed many
studies have since shown that
diarrhea mortality rates in hospital decrease significantly
when ORS is used; part of this
decrease is the avoidance of
intravenous lines and thus the
prevention of their attendant
complications, such as sepsis.
Deaths
✕
60
✕
Diarrheal
Non-Diarrheal
✕
50
40
✕
✕
✕
✕
✕
✕
✕
30
✕
✕
✕
✕
✕
✕
✕
✕
✕
✕
✕
20
10
0
70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90
Year
Infant deaths per 1000 live births, diarrhea and non-diarrhea, from 1970 to
1990, according to the civil register (Egypt). Soc Sci Med 1995; 40: S1-S30.
The question then became how
well ORS could be used outside the hospital setting, in outpatient clinics and communities. Two large cholera
epidemics among refugees provide striking examples. In
1971, ORS was extensively
used in Bangladeshi refugees
in India, with a mortality rate
of 3.6%. By way of contrast, in
1994, ORS was not adequately
available or used in Zaire, and
the mortality rates were as
high as 50%. Another example
is the 1991 cholera epidemic in
Peru, where mortality rates
were less than 1%. This low
mortality was thought to be
due at least partially to the
widespread use of ORS.
In non-cholera diarrheas of
infants and children (which are
by far the most common
worldwide), ORT has also
been shown to significantly
reduce mortality in hospitals
and in the community. Casecontrol studies in both Panama
and Bangladesh have shown
that patients who did not
receive oral rehydration fluids
for their severe diarrhea were
significantly more likely to die.
A community study in
Bangladesh showed that villages using ORS had a significantly lower diarrheal mortality than those not using it.
Several studies have shown
that if ORS is used widely in a
THE NEST N°1 - O CTOBER 1996
community and in out-patient
clinics, admission rates for
diarrheal diseases fall dramatically, and often diarrhea wards
have been able to close.
Longitudinal studies of diarrheal disease mortality in children in Nicaragua, Bhutan and
Egypt (as well as many other
developing countries) have
shown significant decreases
over a period of several years,
following the implementation
of large-scale ORT programs.
This is perhaps best illustrated
by the figure above, which
shows that in Egypt the decline
in diarrheal mortality was
much sharper than the decline
in overall infant mortality.
WHY IS THERE
CONTINUED HIGH
MORTALITY DUE TO ACUTE
DIARRHEAL DISEASE?
• If ORS is not used correctly
its effectiveness is markedly
decreased. This could mean
too little is given (the most
common observation), or it is
not mixed correctly (this is relatively uncommon). Specific
instructions on how to mix and
use ORS must be given to the
care giver by a health worker
who is knowledgeable in its
use.
• ORS may not be available or
the care giver may choose not
to use it. The World Health
Organization is attempting to
3
make ORS available to all
countries of the world; at present it is estimated that about
75% of children have access to
ORS, but only 40%-50% actually
receive it for a diarrheal
episode. In developed countries, like the US, about 300
children still die each year
from acute diarrhea; most of
these deaths could be prevented if ORS were used.
• If severe malnutrition is present, the child may die from
causes related to the malnutrition rather than the acute diarrhea. Indeed most diarrheal
deaths are associated with
malnutrition. The correct use
of ORT (with early feeding)
has been shown to prevent
weight loss due to the diarrheal episode and therefore is
a major therapeutic intervention to prevent the worsening
of malnutrition.
• As deaths from acute dehydrating diarrhea decrease due
to the widespread use of ORT,
the two other major categories
of diarrheal illness, dysentery
and persistent diarrhea, for
which ORT is not effective,
become more obvious and statistically more prominent. It is
estimated that about 75% of all
diarrheal deaths now occur in
those two categories. Effective
use of antimicrobials and diet
are of primary importance in
treatment.
In summary, ORT,
when used correctly,
will definitely lower
acute diarrheal mortality. However diarrhea
will continue to take
children’s lives until
ORT is more widely
applied, and children
with dysentery and persistent diarrhea are
treated appropriately.