The economic value of home asthma interventions.

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The Economic Value of
Home Asthma Interventions
Adam J. Atherly, PhD
A
asthma can be disabled by their illness, especially during
acuteepisodes,andunabletoperformbasiclifetaskssuch
asattendschoolorwork.1–6Properlymanaged,however,
individuals with asthma can lead a normal life, including
participating in sports and other activities, and high-cost
events, such as visits to the emergency department or
inpatient hospital care can be avoided. The review pre-
sented in this supplement to the American Journal of
Preventive Medicine by Nurmagambetov et al.7shows
that comprehensive home environmental interventions
have the potential to be cost-effective interventions for
children with asthma. This is particularly true if the pro-
grams reduce the use of healthcare resources devoted to
treating acute asthma exacerbations brought on by trig-
gers in the home environments.
The National Asthma Education and Prevention Pro-
gram suggests that optimal management of asthma de-
pends on three crucial elements:8,9
sthma is a common and costly chronic illness
affecting people of every economic level, demo-
graphic category, and age group. People with
● Access to high-quality medical care
● Medication management
● Environmental trigger avoidance.
Environmental trigger avoidance includes taking ap-
propriate measures to modify the environment of a per-
son with asthma to minimize exposure to potential trig-
gers. Because most individuals spend large portions of
their lives in their homes, the home is one of the key
environments that should be modifıed.
All seven of the reviewed RCTs of home interventions
found positive effects of the interventions on asthma
outcomes. This strongly suggests that home environ-
mental interventions can be used to improve health, a
necessary—although not suffıcient—criterion for cost
effectiveness.
The reviewed studies do show wide variations in the
costperunitofbenefıt.Ingeneral,theinterventionswith
lowerprogramcostweremorecosteffective.Ofthethree
studies reporting cost per symptom-free day (SFD)
gained, the interventions that reported the lowest cost
per SFD gained also had the lowest program cost10
—$458 per participant and a cost per SFD gained of $12.
Both the Inner City Asthma study and Healthy Homes
studyhadagreaterimpactonSFDgained;however,both
of those interventions were considerably more costly in
terms of program cost, which yielded a higher cost per
SFD gained. Indeed, the highest cost per benefıt was
found for interventions with the highest program cost.
One key factor that determined the cost of the program
was the type of provider used, most obviously due to
differencesinwages.Thishighercostcouldpotentiallybe
offset by higher effectiveness if the more trained person-
nel were more effective. The reviewed studies generally
did not show such an offset.
Overall, the reviewed research indicates that a moder-
ate health impact can be achieved with a relatively low-
cost, low-intensity home environmental intervention.
Such an intervention may have a cost-effectiveness ratio
on par with standard pharmaceutical interventions, such
astheuseofinhaledsteroidsasregulartherapy.Studiesof
inhaled steroids have found that the incremental cost
effectiveness of steroids is $11 per SFD gained11(using
the payer perspective, because most of the home inter-
ventions did not value indirect costs)—little different
from the $12 per SFD reported for home environmental
interventions. So, asthma home interventions can com-
pare favorably to standard pharmacologic treatments.
Itappearsthatsomeeffectcanbeachievedfromevena
relatively low-intensity intervention. For example, Doli-
nar et al.12provided a single asthma education session
delivered in the patient’s home, and reported improved
parental coping and a higher perceived change in the
child’s asthma. This effect can also be observed in Heal-
thy Homes, where both the high-intensity and the low-
intensity arms showed improvement over baseline. A
similar result is also reported in the Community Asthma
Prevention Program, as well as in other asthma inter-
ventions, such as the use of pharmacists to provide
education.13
Although there have been a number of successful ran-
domized clinical trials examining the impact of home
environmental modifıcations, several key research ques-
tions remain unanswered:
From the Department of Health Systems, Management and Policy, Colo-
rado School of Public Health, University of Colorado, Aurora, Colorado
Address correspondence to: Adam J. Atherly, PhD, Department of
HealthSystems,ManagementandPolicy,13001E.17thPlace,Building500,
Room E3315, Aurora CO 80045. E-mail: adam.atherly@ucdenver.edu.
0749-3797/$17.00
doi: 10.1016/j.amepre.2011.05.008
© 2011 American Journal of Preventive Medicine • Published by Elsevier Inc.Am J Prev Med 2011;41(2S1):S59-S61
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● What is the persistence of the effect of home environ-
mental interventions?
Of the reviewed studies, most have a 6- to 12-month
follow-up. The evidence suggests that the benefıts of the
interventions decline over time, but the long-term extent
of the decline is unclear. For example, the Inner City
AsthmaStudyreportedthatunscheduledvisitstotheED
or clinic for asthma care declined by 0.35 per child per
year during the fırst year, and by 0.26 days per year per
child during the second year. This suggests that approxi-
mately one quarter of the benefıts were lost during the
second year. The National Cooperative Inner-City
Asthma Study reported that the maximum symptom-
days declined by ?14.3 per child per year during the fırst
year, and by ?13.3 during the second year, suggesting
thatapproximately7%ofthebenefıtswerelostduringthe
second year.
If the benefıts of home interventions persist over sev-
eralyears,evenrelativelysmalldecreasesinhealthexpen-
ditures may be suffıcient for the program to be cost neu-
tral. Alternatively, if the benefıts diminish substantially,
limited follow-up programs may be effective in sustain-
ing the effectiveness of the intervention.
● What type of professional training is most effective?
There is no consensus in the literature on appropri-
ate training for the individuals performing the home
interventions. In the published literature, studies have
used medical doctors,12environmental counselors/
interventionists,14asthma counselors,15community
health workers,16registered nurses,17home health
nurses,18pharmacists,14and peer educators.19There is
also the possibility of using respiratory therapists.
All of these different professional backgrounds have
strengths and weaknesses. The key trade-off is between a
superior understanding of the community—found in
community health workers, asthma counselors, and peer
educators—and a superior understanding of health and
asthma, exemplifıed by medical doctors, pharmacists,
and nurses. Particularly for low-income and minority
communities, the ability to communicate successfully
with families may be more important for effectiveness
than a fuller understanding of the illness. The personnel
with less medical training also typically have lower sala-
ries, which may lead to more cost-effective treatment,
even with potentially lower effectiveness.
● What is the effect of home interventions on indirect
costs?
Several of the existing studies have not measured indi-
rectcosts,suchasdaysofschoolmissedorcaregiverdays
of work missed. Results from studies that have included
such measures, including the Healthy Homes and Dis-
easeManagementProgram:Asthmasuggestthattheben-
efıts from reduced indirect costs may be substantial. Fur-
ther efforts to quantify and provide a dollar value for
these indirect costs would provide a fuller measure of the
fınancial impact of these interventions.
Although further study is clearly warranted, the scien-
tifıc evidence to date is strong enough to justify the cov-
erageofhomeenvironmentalinterventionsbypublicand
private third-party payers for children with moderate to
severe asthma. There is little evidence, however, on the
optimal design of these home environmental modifıca-
tions.Thislackofevidencearguesbothforfurtherstudies
on such design issues and against any type of regulation
orstandardizationofhomeenvironmentalmodifıcations
until better evidence is available.
Publication of this article was supported by the Centers for
Disease Control and Prevention through a Cooperative Agree-
ment with the Association for Prevention Teaching and Re-
search award # 07-NCHM-03.
No fınancial disclosures were reported by the author of this
paper.
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