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Counting Costs in COPDCounting Costs in COPD: What Do the Numbers Mean? FREE TO VIEW

David M. Mannino, MD, FCCP
Author and Funding Information

From the Department of Preventive Medicine and Environmental Health, University of Kentucky College of Public Health.

CORRESPONDENCE TO: David M. Mannino, MD, FCCP, Department of Preventive Medicine and Environmental Health, University of Kentucky College of Public Health, 111 Washington Ave, Lexington, KY 40536; e-mail: dmannino@uky.edu


FINANCIAL/NONFINANCIAL DISCLOSURES: The author has reported to CHEST the following conflicts of interest: Dr Mannino has served as a consultant for Boehringer Ingelheim GmbH, GlaxoSmithKline plc, AstraZeneca plc, Novartis AG, Merck & Co Inc, and Forest Laboratories Inc, and has received research grants from GlaxoSmithKline plc, Novartis AG, Boehringer Ingelheim GmbH, Forest Laboratories Inc, and Pfizer Inc.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2015;147(1):3-5. doi:10.1378/chest.14-1976
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Published online

COPD is a costly disease. These are words we hear all the time, yet the precise meaning of this phrase is a bit nebulous, and peeking behind the curtain to determine how this is actually measured and evaluated reveals more questions and problems. What are the definitions and approaches to determining these costs?1

  • • Direct medical costs: hospital inpatient payments, physician payments, prescription drugs, medical supplies and devices, nursing home care, and so forth.

  • • Indirect medical costs: premature death, absenteeism, loss of resources, and so forth. There are multiple methods to determining these “costs,” such as the “human capital method” (lost earnings of a patient or caregiver) or the “willingness to pay method” (eg, how much would you be willing to pay to avoid an ED visit?).1

  • • Top-down approach: measures the proportion of a disease related to exposure to the disease or risk factor, and uses aggregated data along with a population-attributable fraction to estimate costs.

  • • Bottom-up approach: estimates costs by calculating the average cost of treatment of the illness and multiplying it by the prevalence of the illness.

  • • Econometric approach: estimates the difference in costs between a cohort of the population with the disease and a cohort of the population without the disease. Regression analysis is used to adjust for polymorbidity.

There are some parallels to how we estimate burden of disease. For example, in the surveillance report for COPD,2 a “COPD death” is determined using the underlying cause of death. The underlying cause of death is established by looking at all the data available on the death certificate, processing it through computer algorithms, and noting the ultimate underlying cause of death. We know, however, that many patients with established COPD have their death attributed to another cause, such as lung cancer or cardiovascular disease.3 Similar findings occur with hospitalizations, where hospitalized patients almost always have multiple reasons for their hospitalization, yet only one can be counted.2 There are multiple places where the process can go awry: underdiagnosis, overdiagnosis, and poor treatment, to name several. This is not only true for COPD, but for the various diseases that occur as polymorbidites with COPD.4

Thus, getting a handle on the costs of COPD has proven challenging. The most recent estimate from the National Institutes of Health included both COPD and asthma, and incorporated direct medical costs (from the US Medical Expenditure Panel Survey [MEPS]) and indirect costs related to mortality, resulting in an overall cost of $68 billion.5 The analysis presented by Ford et al6 is this issue of CHEST (see page 31) uses MEPS data to provide COPD-specific estimates for both direct medical costs and the indirect cost of absenteeism from work. The approach taken in this analysis was an econometric one.

The main data in this analysis come from MEPS. MEPS, which began in 1996, is a set of large-scale surveys of families and individuals, their medical providers (doctors, hospitals, pharmacies, and so forth), and employers across the United States. MEPS collects data on the specific health services that Americans use, how frequently they use them, the cost of these services, and how they are paid for, as well as data on the cost, scope, and breadth of health insurance held by and available to US workers.7

In 2010, the final year of the aggregated data used in the analysis by Ford et al,6 the total estimated medical expenditures were $1,263 billion for 309 million people in the United States.8 For the target population (adults ≥18 years old), the total estimated medical expenditures were $1,148 billion for 233 million people. The analysis included anyone in the survey with International Classification of Diseases, Ninth Revision, Clinical Modification code 127 for COPD. A person would be coded as such if they reported (1) ever having been diagnosed with the condition, (2) the condition was the reason for a particular medical event, (3) the condition was the reason for one or more episodes of disability days, or (4) the condition was “bothering” the person during the reference period. Overall, 10.3 million adults with COPD, as described, incurred total expenses of $101 billion, of which $72.7 billion was attributable to COPD, with the remaining amount attributable to disease other than COPD.6 Thus, the COPD population made up about 4.4% of the adult population, but incurred about 8.8% of the total costs. In the recently published surveillance summary,2 13.7 million people reported a COPD diagnosis, which is 33% higher than the number incurring expenses in this study by Ford et al.6 This is presumably because they had no COPD expenses, but it could also be that they had no events attributed to COPD (because they very likely had some expense-incurring events).

The analysis by Ford et al6 then, in an attempt to estimate the precise, direct medical costs attributed to COPD, uses various strategies to adjust for comorbid medical conditions, complications of COPD, and demographic factors such as age, education, and family income. As they demonstrated in Table 2 in their article,6 adjusting for more factors decreased the differences between the COPD and non-COPD groups. The best estimate of the total direct costs they came up with, after adjusting for 11 conditions not thought to be sequelae of COPD, was $32.1 billion. This, then, provided the basis for the state-specific estimates of COPD costs. Adjusting for additional medical conditions, including some complications or key comorbidities of COPD, would reduce this estimate to $7.3 billion.

So what is the direct medical cost of COPD, and what does this mean? The range for 2010 is from $7.3 billion to $101 billion. If this analysis were replicated for the other leading causes of morbidity and mortality in the United States, such as heart disease, diabetes, and cancer, one would get a similar range of estimates. In the final analysis, however, what may be more important is recognizing that people with COPD incur about double the costs as people without COPD. Furthermore, while direct medical costs of COPD are important, many of the indirect costs, such as disease-related disability and premature mortality, are also critical to the patient population as we assess the burden of this disease.

References

Segel JE. Cost-of-illness studies—a primer. 2006. RTI International website. https://www.rti.org/pubs/COI_Primer.pdf. Accessed September 11, 2014.
 
Ford ES, Croft JB, Mannino DM, Wheaton AG, Zhang X, Giles WH. COPD surveillance—United States, 1999-2011. Chest. 2013;144(1):284-305. [CrossRef] [PubMed]
 
Mannino DM, Buist AS, Petty TL, Enright PL, Redd SC. Lung function and mortality in the United States: data from the First National Health and Nutrition Examination Survey follow up study. Thorax. 2003;58(5):388-393. [CrossRef] [PubMed]
 
Barr RG, Celli BR, Mannino DM, et al. Comorbidities, patient knowledge, and disease management in a national sample of patients with COPD. Am J Med. 2009;122(4):348-355. [CrossRef] [PubMed]
 
NHLBI morbidity and mortality chart book. National Heart, Lung and Blood Institute website. http://www.nhlbi.nih.gov/research/reports/2012-mortality-chart-book.htm. Published 2012. Accessed September 11, 2014.
 
Ford ES, Murphy LB, Khavjou O, Giles WH, Holt JB, Croft JB. Total and state-specific medical and absenteeism costs of COPD among adults aged ≥18 years in the United States for 2010 and projections through 2020. Chest. 2015;147(1):31-45.
 
Medical Expenditure Panel survey. Agency for Healthcare Research and Quality website. http://meps.ahrq.gov/mepsweb/. Published 2014. Accessed September 11, 2014.
 
National health care expenses in the US civilian noninstitutionalized population, 2010. Agency for Healthcare Research and Quality website. http://meps.ahrq.gov/mepsweb/data_files/publications/st396/stat396.pdf. Published 2013. Accessed September 11, 2014.
 

Figures

Tables

References

Segel JE. Cost-of-illness studies—a primer. 2006. RTI International website. https://www.rti.org/pubs/COI_Primer.pdf. Accessed September 11, 2014.
 
Ford ES, Croft JB, Mannino DM, Wheaton AG, Zhang X, Giles WH. COPD surveillance—United States, 1999-2011. Chest. 2013;144(1):284-305. [CrossRef] [PubMed]
 
Mannino DM, Buist AS, Petty TL, Enright PL, Redd SC. Lung function and mortality in the United States: data from the First National Health and Nutrition Examination Survey follow up study. Thorax. 2003;58(5):388-393. [CrossRef] [PubMed]
 
Barr RG, Celli BR, Mannino DM, et al. Comorbidities, patient knowledge, and disease management in a national sample of patients with COPD. Am J Med. 2009;122(4):348-355. [CrossRef] [PubMed]
 
NHLBI morbidity and mortality chart book. National Heart, Lung and Blood Institute website. http://www.nhlbi.nih.gov/research/reports/2012-mortality-chart-book.htm. Published 2012. Accessed September 11, 2014.
 
Ford ES, Murphy LB, Khavjou O, Giles WH, Holt JB, Croft JB. Total and state-specific medical and absenteeism costs of COPD among adults aged ≥18 years in the United States for 2010 and projections through 2020. Chest. 2015;147(1):31-45.
 
Medical Expenditure Panel survey. Agency for Healthcare Research and Quality website. http://meps.ahrq.gov/mepsweb/. Published 2014. Accessed September 11, 2014.
 
National health care expenses in the US civilian noninstitutionalized population, 2010. Agency for Healthcare Research and Quality website. http://meps.ahrq.gov/mepsweb/data_files/publications/st396/stat396.pdf. Published 2013. Accessed September 11, 2014.
 
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