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

to use to measure

measure the individual’s ability to perform activities of daily living(ADLs). These include bathing, dressing, transferring, toileting, and feeding. In one major US interview survey, 77% of persons over the age of 65 y reported no difficulty with ADLs (19).

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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show

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porosis research, but whether hip fractures can be reduced significantly remains to be seen. Other interventions to ameliorate osteoporosis in geriatric individuals, such as calcium intake or exercise, have not yet been proven to be helpful. Perhaps we need to concentrate instead on the pediatric population rather than the geriatric population when speaking about prevention (18). examples

may

in the

shown

Recent reports suggest bone density will (17). This is one of the most promising

These

a task

age groups

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have on older

in some into prevent

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12.

RUDBERG

Measurement issues in preventive strategies: past, present, and future.

Prevention of the chronic health conditions of older people can potentially affect both life expectancy and health. In the past, fatal conditions, nam...
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