issues in preventive
past, present,
and future”2
Mark
A Rudberg,
Sylvia
E Furner,
and
Christine
K Cassel
ABSTRACT Prevention ofthe chronic health conditions older people can potentially affect both life expectancy health. In the past, fatal conditions, namely coronary heart ease,
cancer,
and
stroke,
dominated
work
strategies:
on preventive
of and dis-
major future,
and
arthritis,
to name
a few.
These
conditions
have
effects on, not the quantity, but the quality oflife. In the quality oflife measured in a variety of ways will be nec-
essary to evaluate conditions.
KEY tion
the effects
ofpreventive 1992;55:
strategies 12535-65.
Am J Clin Nutr
WORDS
Measurement
issues,
quality
for nonfatal
oflife,
preven-
Introduction
on
strategies
and
during
life expectancy
it was assumed life through
that
health
a primary
preventive
have had a major this
century.
goal of medicine
strategies.
Implicit
was
in this
impact
In the past, to extend
goal
is the
as-
sumption that an extended life is always beneficial and desirable. To achieve this goal, society has spent enormous energy, money, and time focusing on the fatal diseases, namely, coronary heart disease, cancer, and stroke. is evidenced by the additional
That society 28 y gained
has achieved this in life expectancy
goal for
females in the United States during this century. In working to extend life expectancy, people have assumed that extra years are years ofgood health. However, added years leave and
Prevention
and
To begin
the older often
include,
person
disabling but
conditions
are not
and the sensory by prolonging
at risk for developing limited
impairments life society
(1).
of hearing has traded
age-related,
These
to, dementia,
nonfatal,
nonfatal arthritis,
conditions hip
and vision
or exchanged
fracture,
loss. Thus, one
problem,
early onset of fatal conditions, for another problem, the development ofthe nonfatal, chronic, and often disabling conditions. Preventive strategies for these nonfatal conditions have not been studied as thoroughly; fatal conditions the
more prevention
lead not to changes in the quality oflife.
in the quantity In light ofthis
importantly, unlike prevention of the nonfatal conditions oflife but difference,
the evaluation life expectancy
of preventive interventions is an inadequate outcome.
Am J C/in Nuir
1992:55:12535-65.
Printed
in USA.
of may
rather to changes it is clear that for
of nonfatal This paper
of preventive
strategies
conditions in older from an epidemiologic
of both
the
persons, emphasizing perspective.
conditions will review
© 1992 American
its limitations
this discussion,
ofprevention
an understanding
is necessary.
Prevention
of the definition
is not simply
the inhibition
of disease development. Classically, prevention is defined as having three levels, primary, secondary, and tertiary, each of which is targeted to a particular stage in the continuum of disease (2). The minimize
goal of primary the likelihood is the
colon
that prevention
and future
nonfatal issues
of this
It is thought
present,
fatal and measurement
strategies
with the only outcome ofconcern being mortality. The present increasing life expectancy of the population has put persons at risk for the nonfatal and often disabling conditions of old age, such as dementia, osteoporosis and hip fracture, sensory impairments,
the past,
intake
cancer.
The
prevention is to change of contracting a disease.
of fiber goal
in the
diet
ofsecondary
to decrease
prevention
is the routine testing due to cancer. The
prevention is to minimize parent disease. An example
the complications of this is the
after
Because studied,
include
In the United these causes, is important not caused rates
of death neither
issues
first.
has been
I
From
prevention
For the purposes heart
at the outset
all the changes from
in the United
States,
that
on the classic
be it risk factor
the Section
preventive
However, measures
For
has decreased
dramatically,
the
magnitude
epidemiologic
Internal
ofthe
it have
example,
is the leading
modification,
of General
of this paper,
which
nor
better of fatal
cancer, and stroke. in those 65 y are due to
disease,
sequence
ap-
disease,
in life expectancy.
cardiovascular
the temporal
based
has been
to the
can be explained by risk factor modification The study and prevention offatal diseases an effect,
ofoccult blood goal of tertiary
States 75% of deaths either individually or in combination. to note
of
sub-
of clinically of rehabilitation
use
conditions
related
coronary
risk
cancer.
of the fatal
will be discussed
diseases
tality
for colorectal
measurement
diseases fatal
surgery
prevention
the
is to detect
clinical disease. An example in the stool to detect bleeding
services
risk factors to An example
morcause
but change
alone (3). in older populations method.
To measure
a disease,
or a therapy
Medicine,
Department
of
Medicine; ofChicago; of Public
The Harris School of Public Policy Studies, The University and the Epidemiology and Biostatistics Program, The School Health, University oflllinois at Chicago. 2 Address reprint requests to MA Rudberg, Section ofGeneral Internal Medicine, Department of Medicine, The University of Chicago, 574! South Maryland Avenue, Box 72, Chicago, IL 60637.
Society
for Clinical
Nutrition
l253S
Downloaded from https://academic.oup.com/ajcn/article-abstract/55/6/1253S/4715422 by East Carolina University user on 14 January 2019
Measurement
12545
RUDBERG
on a fatal condition, we investigate mortality rates ulation. And although this is clearly an important
in the popmeasure, it
is a limited
changes
measure
because
it says
quality of life. Thus the time from quantity to quality oflife, in life expectancy
will
little
has come especially
be minimal
(4).
about
to switch because We
the
in
the emphasis future increases
should
focus
on im-
lative
life exposure
(eg, smoking
and
cancer)
is a more
important
measure of exposure than any other measure whereas in others present exposure is more helpful (eg, smoking and cardiovascular disease). The whole issue ofintervention timing is now beginning to receive greater study because of the importance of understanding
the timing
ofan
exposure
to an outcome.
In those over the age of 85 y, because the risk ofdeath is high and because death is often related to multiple causes, sometimes it is difficult expectancy. in old age.
to determine
the effect
that
In general the risk ofdeath In fact it has been calculated
an exposure
has on life
increases exponentially that for individuals over
the age of 30 y the risk of death doubles every 8 y (5). In older populations the risk of death is high regardless of what intervention is instituted; this is due to competing risks. For example, if a person does not die of heart disease, he is at risk for cancer. Also, in older persons death may be due to multiple causes or interacting risks. For example, an older person may die as a result ofpneumonia due to cancer aggravated by congestive failure due to coronary heart disease. To further complicate issue poor death certificate information makes determining
heart this
actual causes of death difficult. So not only is it difficult to show an effect secondary to a high mortality rate, it is also difficult to determine a single cause of death. Another consideration is the relative efficacy of a particular therapy. Even if preventive therapies are known to be effective under ideal circumstances, in the real world efficacy measures include the problems of health provider compliance with recommendations and the variability of patient responses. A simple example is influenza vaccination, although therapies for the fatal conditions follow the same pattern. Good preventive medicine dictates that influenza vaccinations should be given to persons over the age of 65 y and others who are at risk. Unfortunately, however, they are not often given and even if they are they do not always work well. Influenza vaccinations at best are only 70% effective (6). In addition, those who are ill do not respond well to vaccine (7). More importantly, it has been shown that many physicians routinely do not prescribe vaccinations because of their own and their patients’ attitudes and behaviors (8). This illustrates the point that preventive measures are probabilistic, not absolute, and that behaviors play an important role as we!!. Likewise, one can think about the efficacy of blood pressure medication or the reduction of cancer risk
AL
factors and see how important the concept ofefficacy is but how little it is talked about in the prevention literature ofolder people. Finally, because ofthe success oftherapies for fatal conditions, people with these conditions can now live longer. As a result of insulin,
blood
pressure
medication,
and
antibiotics,
individuals
who suffer the onset ofa fatal disease (eg, stroke) are now better able to survive. The consequence of survival, however, is that a proportion of the fatal conditions have become chronic conditions, leaving individuals who would have died in the past with a physical deficit such as hemiplegia or congestive heart failure (9).
The
come
classic
does
approach
not
allow
“fatal conditions dividual’s quality beginning
to be addressed,
which
may
at the
mortality
of the
effect
out-
that
these
could
have
been
called
an
“inter-
because the outcome for a person is no longer severe and lasting deficits, such as immobility,
be overwhelming
for an individual.
morbidities
In contrast, plies,
the nonfatal
do not
include fracture their
cause
conditions,
death,
but
cause
as the terminology disability.
These
im-
conditions
dementia, arthritis, hearing loss, osteoporosis, and hip to name a few. Measuring these conditions and assessing implications
difficult diagnosis the
only
measurement
turning into chronic diseases” have on an inof life. The outcome of this shift, which is
mediate outcome” death, but rather
The
of looking for
for
to determine specifies
date
of onset.
remains
an
individual
is not
an
easy
task.
when a condition begins because when the disease is first diagnosed Thus
the
natural
history
It is
time of but not
of these
conditions
vague.
As an illustration
of some
ment
of chronic
or nonfatal
and
hip fracture.
Dementia
creases
in incidence
and
important diseases,
points
about
consider
both
is a common
prevalence
with
disorder, age. The
type of dementia is dementia of the Alzheimer prevalence rate ofdementia in community-dwelling the age of 85 y is 20-25% but has been reported mately
twice
as high
highly
disabling;
in at least
one
in fact behavioral
measuredementia
study
problems
which
in-
most common type (10). The persons over
as approxi-
(1 1). Dementia associated
is
with
de-
mentia are often treated with psychotropic medication, which can result in the decline of an already low level of cognitive function. Other therapies can also cause side effects and do not reverse the dementing process. Although speculation of several potentially etiologic risk factors is noted in the literature, there is no is fair
known
risk
to state
factor
that
on which
the
pecially
in consideration
increase
dramatically.
number
of the At present
that will reduce this number. of other diseases may actually vidual lives in a disabled state, tioned
In the with
aging
of the
no
interventions
future
it
dementia,
es-
population,
will
are
known
In fact our successful treatment lengthen the time that an mdia situation that some have ques-
(12).
As is true been
to intervene. of persons
for dementia,
occurring
with
osteoporosis
increasing
and
frequency.
hip fracture Over
250
have 000
hip
fractures per year occur in the United States (13). This number will increase, especially as the individuals in the population age, because
it has
been
noted
that
the
number
of hip
fractures
in-
creases exponentially for those over the age of 45 (14). The two major risk factors for hip fractures in older individuals are falls and osteoporosis. Although some promising work at identifying
people
who
are at the greatest
risk
for falls
may
lead
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proving the quality of the additional years we have gained, in part through effective preventive strategies of fatal diseases. To measure the effect of prevention intervention, it is important, especially in older persons, to understand the timing of the intervention. Although good health practices at any time of life may be helpful, timing may be crucial for achieving the desired effect. For example, hypertension, which is only controlled late in life, may have already created physiological impairment; treatment at an old age may be helpful but will not prevent complications that have already occurred. To be sure, there is evidence that regression of some diseases can occur (eg, atherosclerotic plaques), but regression for many other health problems has not been shown to be possible. In some conditions cumu-
ET
MEASUREMENT to interventions that prevent dividuals, few public health falls ( 1 5). Likewise prevention viduals has not been proven menopausal
women
or postpone fractures initiatives are known of osteoporosis
in elderly
to be helpful.
estrogens
(16); what effect estrogens
have
Certainly,
Many
the magnitude
can
cause
changes
category cannot nor about the functional
the quality
chronic
problems
Obviously,
of life,
but
these con-
Disabmlity of disease
is thought
of as being
consequences.
one step
A disease,
such
in the progression
as degenerative
disease, causes pathology. This can lead to an impairment, an alteration ofan organ system, for example, a limitation in range of movement of a joint. This can then lead to disability, such as the inability to walk. Several points should be made about disability. First, the relationship between the condition and the disability is complicated. Many conditions can impinge on a particular disabmlmty, a usual scenario in older persons. Likewise a person can have many conditions and yet have no disability. Second, for each ofdisability
there
are many
ofimpairment.
For
different
physical
scales
However,
for females.
this
functioning
percentage
declines
measure
of physical
Another
with
we commonly
age
and
functioning,
is lower albeit
a
more complex activity, is instrumental activities of daily living (IADLs). These activities include shopping, cooking, cleaning the house, and managing money. In the same national survey mentioned above, more people reported difficulties with IADLS than
with
ADLS.
age and gender. gross
mobility
Again,
Other and
the same
measures
physical
trends
were
ofphysical
performance,
seen
as above
functioning both
ofwhich
for
include may
be
important in relation to mobility and strength disorders. A third consideration regarding disability is the need to specify the endpoint: is it defined as the difficulty or the inability to accomplish
the task?
fort and pain whereas
Difficulty
with
the consequences
a task
may
ofinability
does
not
able
with the quality ofa person’s tasks on any of the
to perform
cognitive, always
the individual
emotional,
have
social,
However, a negative
may
lessen
the presence impact
(eg,
of
many
individual
mnterprets
to life.
Health
status measure
different
that
disability
that
oflife
is health
ofquality
meanings
but
nevertheless
gives
meaning
status,
and
which
is a valuable
has
variable
to study (20). Self-perceived health status, though ligned, is one particular measure shown to be highly
much mapredictive
of mortality and disability (21). It seems to integrate formation about the individual and gives a measure
much inof satisfac-
oflife.
However,
standardized differing
these
are individually
to the individual. goals
with
Obviously,
different
based
and
different
somewhat
persons
have
wants.
Conclusions The
nonfatal
conditions
need
are generally
a functional with many
to be studied
not preventable
outcome different
more
extensively
that can endpoints.
in the future.
of life, an important measure for all persons, in many ways, including length oflife, medical abilities,
and
perceived
about measuring prevention efforts. consider for health
as we determine care.
health
outcomes All these
status. other issues how
and
Quality
can be measured conditions, dis-
In the future
we must
think
than death when evaluating are increasingly important to target
our
are
be measured These con-
limited
to
resources
U
References
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physical,
quality
ditions
joint
disability
being
related to disability, in many domains
fectively.
the level
the
tion
Because many ofthese conditions can cause disability, a short discussion about disability is warranted. Disability, defined as a restriction in the ability to accomplish a task normal for an individual, has many dimensions: physical, such as the inability to feed oneself; cognitive, such as dementia; emotional, such as being depressed; and social, such as the inability to interact ef-
associate
to support
task.
demented or retarded individuals have very full lives as do many persons with quadriplegia). It is evident that functional ability can be related to quality of life for an individual, but it is how
many
tell us about the severity of the disease limitation that it creates.
services
of the
not
Another
a dichotomous
for social
of life for an individual.
disability
etidronate in osteo-
Disability
type
above,
levels
them.
in quality
Certainly,
to be helpful
ofthese
and how little we can do to prevent ditions disease
people
life.
in less certain.
increase with developments
be the need
include
discom-
to accomplish
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12.
RUDBERG