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* From the Department of Pharmacy (Drs. Strassels and Sullivan), University of Washington, Seattle, WA; Kaiser Permanente Center for Health Research (Dr. Smith), Portland, OR; and Global Health Outcomes (Dr. Mahajan), Glaxo Wellcome Inc., Research Triangle Park, NC.
Correspondence to: Scott A. Strassels, PharmD, BCPS, Department of Pharmacy, University of Washington, Box 357630, Seattle, WA 98195; e-mail: scotts1{at}u.washington.edu
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Abstract |
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 TOP Abstract IntroductionMaterials and MethodsResultsDiscussionConclusionReferences |
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Design: Data for this study were derived from the 1987 National Medical Expenditure Survey. A societal perspective was adopted for this analysis.
Patients
or participants: All persons 
40 years old with resource use
or expenditures for chronic bronchitis, emphysema, or nonspecific
chronic airway obstruction were included in this study.
Results: Mean per-person direct medical expenditures among persons with COPD were $6,469 (1987 US dollars), about 25% of which was COPD related. Approximately 68% of direct medical expenditures in persons with COPD were for inpatient hospitalization.
Conclusions: COPD causes a large societal burden of illness that is expected to increase. This study provides a valuable foundation and historical measure against which to compare other estimates.
Key Words: COPD • cost of illness • economics • National Medical Expenditure Survey
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Introduction |
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TOPAbstractIntroductionMaterials and MethodsResultsDiscussionConclusionReferences |
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Chronic lung diseases, including COPD (chronic bronchitis, emphysema) and asthma, caused approximately 5.6% of all deaths in the United States in 1997 and are responsible for about 3 million deaths worldwide each year.3 4 Respiratory diseases, and COPD in particular, are among the three main causes of lost workdays, and are the fourth most common noncommunicable cause of disability, behind neuropsychiatric disorders, cardiovascular disease, and cancer.3 4
In the United States in 1996, chronic bronchitis affected approximately 14.2 million persons and emphysema affected about 1.8 million persons.5 The prevalence of chronic bronchitis in 1996 was approximately 53.5 persons per 1,000 persons, while the prevalence of emphysema was about 6.9/1,000 persons. This rate represents an increase in chronic bronchitis of > 10% from 1986 to 1988 and of nearly 57% from 1979 to 1981.6 The prevalence of COPD is higher in women than men, although chronic bronchitis is more common among women and emphysema is more common among men. In 1997, COPD and allied conditions (International Classification of Diseases, Ninth Revision; Clinical Modification codes 490 to 496) were the fourth-highest cause of death in the United States, behind heart disease, cancer, and cerebrovascular disease, with an age-adjusted death rate of 21.1/100,000 persons.3 6 7
In addition to causing morbidity and mortality, COPD affects medical resource use, daily life, work productivity, self-reported health status, and other activities for persons with the disease.8 Estimating the economic and medical effects of COPD is difficult, however, and there are very little data about the burden of illness imposed by this condition on society. Despite the assumption that persons with COPD use substantial amounts of medical resources and incur significant expenditures, very little information is available in the published biomedical literature. A search of the 1975 to 2000 HealthSTAR and 1966 to 2000 MEDLINE databases revealed only three other evaluations of the economic burden of COPD on society.9 10 11
The purpose of this study was to describe the medical resource use and costs incurred by community-based individuals with COPD in the United States from a societal perspective. The intended audience for this analysis includes health-policy decision makers, health-care payers, and clinicians.
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Materials and Methods |
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TOPAbstractIntroductionMaterials and MethodsResultsDiscussionConclusionReferences |
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The 1987 NMES was designed to provide extensive information on health expenditures by or on behalf of families and individuals, the financing of these expenditures, and each person’s use of these services, for the purpose of making public-health policy.13 The inclusion of economic data in the NMES is a significant advantage over other population-based national medical surveys. Although data from the 1987 NMES are now > 12 years old, and some of the data from the 1996 Medical Expenditure Panel Survey (MEPS) have been released, the data reported herein are the most recent of their type available. Estimates generated from this database provide a valuable look into the health and health-care changes over the past decade, and provide an important foundation to compare to newer estimates.
Participants were chosen using a multistage sampling design.12 The NMES was designed to provide information about health-care resource use and health insurance coverage for making public-health policy; therefore, groups of people with characteristics of interest were oversampled, including poor and low-income families, black and Hispanic individuals, elderly persons, and functionally impaired persons.12 13 The NMES excludes persons in the military and homeless individuals. Data pertaining to institutionalized persons were not included for the purposes of this analysis.
The data in the NMES were provided by the individuals who participated in the survey. To reduce the influence of biases inherent in self-reported information, the NMES included the Medical Provider Survey (MPS) and the Health Insurance Plan Survey (HIPS).14 The MPS used information from physicians, hospitals, outpatient clinics, emergency departments, and home-health agencies. The HIPS collected data about private health insurance of participants in the NMES. Expenditures for medical provider visits and inpatient hospitalizations are reported as total charges, except when charges were reduced to amounts allowed by third-party payers or when a total charge was not specified for a given service.15 In these cases, a dollar value was imputed from expenses from similar services. Expenditures for prescription drugs reflect the total amount paid out-of-pocket and by third-party payers.16 All expenditures are reported in 1987 US dollars to avoid errors associated with inflating estimates to more recent dollar amounts.
The sample for this study was all civilian noninstitutionalized persons
40 years old who reported resource use or expenditures for COPD,
defined as chronic bronchitis, emphysema, or chronic airway
obstruction, not elsewhere classified (International
Classification of Diseases, Ninth Revision; Clinical Modification
codes 491, 492, or 496, respectively).7
A societal
perspective was adopted for this analysis. Estimates were made for
direct medical costs and resource use and for indirect resource use.
Individuals were classified as having public, private, or no health insurance, based on the type that paid the largest percentage of their expenditures. Public insurance included all state and federal health insurance programs, such as Medicare, Medicaid, programs to benefit military personnel and dependents, and other public assistance programs.
Five levels of smoking history were constructed: never smokers, defined
as persons who had smoked < 100 cigarettes during their lives;
persons with < 50 pack-year (PY) history of exposure; persons with
50 PY history of smoking exposure; persons who were smokers, but
whose PY history was unknown; and persons for whom smoking status was
unknown.
Direct Medical Resource Use and Expenditures
Direct medical resource use and expenditures were classified
into the numbers of inpatient admissions, visits to medical providers
in outpatient clinics (outpatient clinic visits), visits to medical
providers in freestanding clinics or offices (office visits),
prescribed medications, and emergency department visits
incurred.15
Office visits to medical providers were
further classified into office visits to specialists, generalists, and
other medical providers. Generalists were defined as family practice,
internal medicine, and general practice physicians, as well as nurses,
nurse practitioners, and physician’s assistants. Specialists included
all other medical providers, while visits to unknown providers
indicated that data were missing. Counts of the number of prescribed
medications included both prescription and over-the-counter drugs
prescribed by licensed practitioners. Over-the-counter medications that
were not prescribed were not included in the NMES.12
Resources used and expenditures incurred by individuals with COPD were classified as those related to COPD (COPD related) and all resources used and expenditures incurred by individuals with COPD during calendar year 1987. In the NMES, each resource used or cost incurred could be attributed to up to four reasons. COPD-related resources and expenditures were any of those listed above that participants attributed to at least one of the conditions used to define COPD. Direct medical resource used and expenditures incurred during 1987 were also stratified by demographic and health-status variables to estimate the influence of age, sex, race, insurance, smoking history, self-reported health status, and the number of selected comorbid conditions.
Indirect Resource Use
Indirect resource use was estimated as the number of bed days,
restricted activity days, and lost workdays experienced during 1987.
Bed days were days in which the person spent at least half the day in
bed.17
Restricted activity days occurred when the person
cut back on normal activities for as much as a day. Lost workdays were
those when the person missed at least half the day of work. Lost
workdays excluded work around the house; restricted activity days
excluded both lost workdays and bed days. Time spent in a hospital was
not included in this category of resource use. It is possible that a
person could meet the criteria for bed days and lost workdays on a
given day; therefore, bed days could overlap with lost
workdays.17
Statistical Analysis
SAS software (Version 6.12 of the SAS System for Windows; SAS
Institute, Cary, NC) and STATA (Release 6; Stata Corporation; College
Station, TX) were used to perform the descriptive analyses
reported.18
19
Parametric assumptions regarding confidence
intervals for expenditures were verified using bootstrap methods.
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Results |
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TOPAbstractIntroductionMaterials and MethodsResultsDiscussionConclusionReferences |
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Prescribed Drugs
Among persons with COPD, the most commonly prescribed types of
drugs were xanthines (theophylline, aminophylline, dyphylline, and
oxtriphylline), {beta}-adrenergic agonists, antihypertensives and
diuretics, and benzodiazepines and other anxiolytics (data available on
request). These classes of drugs were used by 69.7%, 46.5%, 40.8%,
and 21.9% of persons with COPD, respectively. Ipratropium bromide,
nicotine polacrilex gum, and oxygen were used by 2.6%, 0.9%, and
1.8% of individuals with COPD, respectively. Persons with COPD used
prescribed drugs of all types frequently.
Ambulatory Care
On average, persons with COPD visited outpatient clinics twice,
generalists more than four times, and specialists almost five times
during 1987 (Table 2)
. Approximately 20% of outpatient clinic visits,
22% of visits to specialists, and 36% of visits to generalists were
COPD related.
Indirect Resource Use
On average, persons with COPD reported 24.4 bed days, 27.5
restricted-activity days, and 3.6 lost workdays, of which approximately
66%, 58%, and 28% were COPD-related, respectively. The difference
between the number of bed days reported and the number of lost workdays
is thought to be a reflection of the generally advanced age of persons
with COPD, and the degree to which persons with COPD are retired or
disabled.
Per-Person and Total Direct Medical Expenditures
Persons with COPD spent an average of $6,469 each (Table 3
). Overall, about 25% of costs were related to COPD. About 68% of
total direct medical expenditures were for inpatient hospitalizations.
Prescribed medications accounted for approximately 8% of direct
medical expenditures. Approximately 20% of persons with COPD
accounted for about 74% of total expenditures (Fig 1
).
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Discussion |
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TOPAbstractIntroductionMaterials and MethodsResultsDiscussionConclusionReferences |
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In 1987, community-based persons with COPD spent approximately $6,500 (1987 US dollars) each, about 26% of which was related to COPD. These results provide evidence that persons with COPD incur significant direct medical costs and resource use, and that COPD causes a large human and economic burden to society.
Of nearly 35,000 civilian, noninstitutionalized persons surveyed in the 1987 NMES, about 0.7% of the NMES sample reported medical resource use or expenditures due to COPD. In 1987, among noninstitutionalized civilians, approximately 12.7 million persons had chronic bronchitis and about 2 million had emphysema, or approximately 6.1% of this segment of the population.21 22
The estimated prevalence of COPD in the NMES sample is lower than a formal estimate of COPD epidemiology for several reasons. First, the NMES was designed to collect information about health-care costs and health insurance for making public policy, not for making robust epidemiologic estimates. Second, the NMES is useful to estimate costs and resource use, but it includes only civilian, noninstitutionalized persons living in the community, and is oversampled to better represent minority groups, elderly persons, and other people expected to have decreased access to health care. Persons who received care at Veteran’s Administration medical centers, individuals living in nursing homes and other institutions, and the homeless are not included in these estimates. Third, the NMES provides only a measure of persons with COPD who were treated for their condition. Thus, people who did not use any direct medical resources or did not incur direct medical expenditures during 1987 were excluded. Most people with a chronic disease tend to be mildly affected, and less severely ill persons are less likely to use medical resources and to incur costs as a result of their disease. Therefore, the prevalence of COPD in the NMES is expected to be substantially less than a robust estimate of prevalence. Furthermore, the people who are included are likely to be more severely ill, since most people with a chronic illness are mildly affected and are less likely to seek or need medical attention for their disease. Fourth, the definition of COPD adopted for this study was relatively restrictive, excluding asthma and other conditions often included in estimates of this type of respiratory disease. Last, the data in the NMES are self-reported, and although the NMES included the MPS and HIPS, as well as other features to help adjust for possible errors and biases, estimates based on these data are still subject to known biases.23 24 25
In this analysis, we evaluated the contribution of comorbidity in terms of several diseases that are known to cause substantial morbidity and mortality. A large majority of persons with COPD had at least two of the comorbid illnesses in addition to their respiratory disease. This finding supports the belief that persons with COPD experience a substantial burden due to comorbid conditions above that caused by their respiratory disease.
Treatment for COPD is generally limited to supportive and symptomatic measures, including hospitalization and the use of prescribed medications. In 1987, hospitalization accounted for nearly 70% of total expenditures incurred by persons with COPD. Although a wide variety of drugs were used in 1987 to help treat COPD, ipratropium bromide metered-dose inhaler was the only drug specifically indicated for the treatment of bronchospasm associated with COPD. Despite its approval by the US Food and Drug Administration in early 1986, only 2.6% of persons with COPD in this study obtained this drug by prescription during 1987. Similarly, the US Food and Drug Administration approved nicotine polacrilex gum in early 1984 for use as an adjunct to smoking cessation efforts. Yet, despite the importance of exposure to tobacco smoke as a cause of COPD, < 1% of persons with COPD were prescribed this drug during 1987.
Several factors may have contributed to the low use of these drugs in 1987. At the time the NMES data were collected, clinicians and patients may not have been aware of ipratropium or its role in the treatment of COPD. Patients may have had medical insurance that did not cover prescription medications, such as Medicare. The low rates of use may reflect the low perceived clinical usefulness of these drugs at the time, as well as their side effect profile, barriers to obtaining the drug, the natural lag time between the introduction of a drug and adoption of its clinical use, and cost during the survey period.
The difference between expenditures for inpatient hospitalization and the other categories examined suggests enormous potential for development of interventions to help decrease the economic burden of COPD on society. Approximately 74% of total direct medical costs were incurred by about 20% of persons with COPD. Inpatient hospitalization accounted for approximately 74% of COPD-related expenditures and > 68% of total expenditures among persons with COPD, despite the fact that only 11.2% of persons were hospitalized for COPD-related reasons. Thus, interventions that identify persons at risk for hospitalization or that result in less frequent or shorter admissions are most likely to be cost-effective from a societal perspective and are likely to help decrease net expenditures.
There are several limitations to the data used in this study. First, the data in the NMES are > 12 years old; however, there are no national estimates of medical expenditures available from 1987 to 1996, when the MEPS was done. Thus, the NMES does not represent changes in health-care resource use that have occurred since 1987, including the rapid increase in health-maintenance organizations as providers of health care. Although estimates from the MEPS will provide more current view of health-care expenditures and resource use, these data are not yet completely available. Thus, the NMES is the most recent data of this type available for this type of analysis. The current study reported herein provides a valuable baseline and historical measure against which to compare estimates that may be made using the MEPS, and contributes to a body of literature that has reported cost estimates made using data from the NMES.24 25 26 27 28 29 30 31 32 Second, the estimates presented underrepresent the societal burden of illness caused by COPD in the United States in 1987. The NMES was designed to provide estimates of health-resource use and health insurance among civilian, noninstitutionalized persons to help guide public-health policy. Because of the methods used to construct the NMES sample, the data cannot be used to make robust estimates of prevalence. For example, some persons with COPD who used direct medical resources or incurred expenditures may have received care during 1987 at Veteran’s Administration hospitals, lived in nursing homes, or were homeless, and were not included. Third, although the NMES does not include disease severity data, persons included are likely to be more severely ill. This is because most people with a disease are mildly affected, and may be less likely to seek medical attention. Fourth, up to four reasons for use of a resource may be specified in the NMES, making attribution difficult. Thus, this potential for misclassification may affect the comparison of resource use and costs incurred by persons with COPD to that reported by persons in the control group. Last, it may be difficult to understand estimates in 1987 dollars in terms of the health-care market of today.
Total spending for acute and chronic medical care in 1987 was approximately $572 billion (1993 US dollars), not including nursing-home care, dental care, or insurance-claims processing.32 Of this amount, cardiovascular disease accounted for the largest proportion, $80 billion (13.9%). Respiratory disease was the sixth-largest category (6.7%), after injury and long-term effects (12.1%), cancer and genitourinary conditions (8.7% each), and pregnancy and birth-related conditions (6.9%). Inpatient hospital costs were the largest component, accounting for 57% of the total, followed by ambulatory-care visits (16%), hospital outpatient services (11%), and prescriptions (7%). In comparison, 1987 direct costs for chronic medical care were estimated to be approximately $425 billion (1990 US dollars), or about $3,074 per person.30
The NMES has been used to estimate the costs due to a variety of health conditions. Overall, the three most expensive conditions were trauma-related disorders, all cancers, and all heart conditions (excluding ischemic heart disease and congestive heart failure), which were estimated to cost approximately $28 billion, $26 billion, and $23 billion, respectively.31 Diabetes was estimated to cost almost $11.4 billion, and expenditures for arthritis were almost $10.7 billion (1987 US dollars). On a per-person basis, the most expensive condition during 1987 was cerebrovascular disease, which cost approximately $5,200 per person affected (1987 US dollars). Gallbladder disease and cancer ranked second and third, with estimated expenditures of about $3,900 each (1987 US dollars). Diabetes was estimated to cost approximately $1,600 per person (1987 US dollars). Although defined differently than in this current article, COPD was estimated to cost approximately $4.4 billion (1987 US dollars), or nearly $500 per person.
Three previous studies have estimated the economic burden of COPD. Each, however, evaluated different populations than the current study. The first used the 1970 Health Interview Survey to examine the societal costs of emphysema.9 These authors estimated that the total costs due to emphysema in 1970 were > $1.5 billion (1970 US dollars) and that hospital care was responsible for about 57% of direct costs. More recently, persons with COPD who were enrolled in Medicare spent nearly $8,500 (1992 US dollars) each, almost 2.5 times the amount for persons in Medicare without COPD.10 In the third and most recent analysis, persons with chronic bronchitis spent almost $770 (1996 US dollars), while persons with emphysema spent nearly $1,285 (1996 US dollars). These authors found that hospital care accounted for 54% of total direct costs for chronic bronchitis, and nearly 72% of total direct costs for emphysema.11 Medications accounted for > 37% of direct costs among persons with chronic bronchitis, and approximately 25% of direct costs among persons with emphysema.
During 1987, total asthma-related direct medical costs were approximately $2.9 billion (1987 US dollars), or about 60% more than those for COPD.32 Per-person expenditures, however, reflect a different profile. In the current study, COPD-related expenditures were > $1,650 per person, and total direct medical costs were nearly $6,500 per person (1987 US dollars). Approximately 4.65 million persons with asthma used resources in 1987; therefore, direct medical costs were about $627 per person.
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Acknowledgements |
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Footnotes |
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This study was performed at the University of Washington, Glaxo Wellcome, and the New England Medical Center.
This study was supported in part by a grant from Glaxo Wellcome Inc.
Received for publication January 18, 2000. Accepted for publication September 12, 2000.
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