Economic and Health Consequences of COPD Patients and Their Spouses in Denmark—1998–2010

Abstract

Objective: Chronic Obstructive Pulmonary Disease (COPD) is among the leading causes of morbidity and mortality worldwide, but longitudinal studies of the economic consequences of COPD are scarce. This study evaluated the economic consequences of COPD patients in Denmark and their spouses at a national level before and after initial diagnosis. Methods: Using records from the Danish National Patient Registry (1998–2010), 171,557 patients with COPD and 86,260 spouses were identified; patients were compared with 664,821, and the spouses with 346,524, all controls were randomly selected and matched for age, gender and residence. Direct and indirect costs, including frequency of primary and secondary sector contacts and procedures, medication, unemployment benefits and social transfer payments were extracted from national databases for patients, spouses and controls. Results: COPD patients are earning approximately half of that of controls before diagnosis. After diagnosis this effect diminishes due to people getting older and retiring from work (65 years). Total health expenses are more than twice as high in the COPD group regardless of age and gender compared to controls. Spouses of COPD patients had significantly higher rates of health-related contacts, medication use and higher socioeconomic costs compared to controls. The employment and income rates of employed spouses of COPD patients were significantly lower compared to controls. Conclusion: This study provides unique data on the economic consequences of COPD patients in Denmark and their spouses as well as displaying the serious health consequences for the individual spouse and society. Second, data shows substantial impact of COPD on income level and health expenses regardless of age and gender. It could be speculated that early identification and intervention might contribute to more health and economic equality between patients and controls

Keywords :

• Chronic obstructive pulmonary disease
• economic burden
• employment
• health costs
• illness costs

Introduction

Chronic Obstructive Pulmonary Disease (COPD) is among the leading causes of morbidity and mortality worldwide, but longitudinal studies of the economic consequences of COPD are scarce (1, 2). There is and even more pronounced lack of studies on the consequences of being a spouse of a patient with a chronic disease.

Smoking, not necessarily number of pack-years, is slowly declining in the Western world but continues to rise elsewhere and it is estimated that the global impact of COPD will increase in the years to come (3–5).

Estimates of COPD prevalence in industrialized countries range widely reflecting both true differences as well as differences in the definition of COPD and in the diagnostic tools used. Most studies find a 10–15% ­prevalence of COPD in people from 35–40 years and older (6–11). The 17.4% prevalence of COPD in Denmark reported in The Copenhagen City Heart Study is among the highest in the world (12).

The burden of COPD on the health care sector is ­substantial and has been described and documented in previous cost-of-illness studies concentrating on ­treatment of COPD and not considering co-morbidity (13–20). Furthermore, the information and assumption of costs have focused on direct costs because indirect costs have generally not been available. Thus, an ­estimate of total costs of COPD has not yet been achieved.

In Denmark, it is possible to calculate direct and indirect costs of any given disease because information from public and private hospitals and clinics in the primary and secondary care sectors, including medication, social factors, educational level, income and employment data from all patients is registered in central databases and can be linked by the unique civil registration number assigned to all Danish citizens facilitation easy and ­reliable linkage of data. The aim of this study was to evaluate the direct and indirect costs of COPD patients and their spouses in Denmark with specific focus on age and gender before and after initial diagnosis.

Methods

In Denmark, all hospital contacts, primary and secondary diagnoses are registered in the National Patient Registry (NPR) (21). The NPR includes administrative information, diagnoses, and diagnostic and treatment procedures using several international classification systems, including the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10 Version: 2010).

The NPR is a time-based national database that includes data from all inpatient and outpatient contact, so the data that we extracted are representative of all patients in Denmark who has received a first time primary and secondary diagnosis of COPD irrespective of other diagnoses. As data are available for the entire observation period, we can trace patients retrospectively and prospectively relative to the time of their diagnosis. Furthermore, all contacts in the primary sector (general practice and specialist care) and the use of medications are recorded in the databases of the National Health Security and the Danish Health and Medicines Agency, respectively. Even though the study is evaluating a relatively long period of time, there is a risk of underestimating the number of patients with COPD, since those with a contact in the primary sector only but not in the secondary sector are recorded as having had contact but not as having received a diagnosis.

We extracted the following first time primary or secondary diagnoses from the NPR in the time period 1998–2010: “J44 Other chronic obstructive pulmonary disease” compromised by the following sub-diagnoses: “J44.0 Chronic obstructive pulmonary disease with acute lower respiratory infection”, J44.1 Chronic obstructive pulmonary disease with acute exacerbation, unspecified,” “J44.8 Other specified chronic obstructive pulmonary disease” and “J44.9 Chronic obstructive pulmonary disease, unspecified.” “J43 Emphysema” and “J47 Bronchiectasis” was not included. Data on disease severity was not available.

Using data from the Danish Civil Registration System including information about all partners, their marital status, social factors, employment, incomes, pensions etc. (22), we randomly selected controls of the same age and sex as the patients. Nor the NPR or any other of the national databases contains information about smoking status.

Social compensation was performed by selecting control subjects residing in the same area of the country as the patients and with the same marital status. The ratio of control subjects to patients was 1:4. Data from patients and matched control subjects who could not be identified in the Income Statistics database were excluded from the sample. More than 99% of the observations in the two groups were successfully matched. Patients and matched controls were followed from 1998 to 2010. If a patient or control was not present in the registry on 1 January each year due to death, imprisonment or immigration, the corresponding control or patient control was not included in the data set for that year.

All spouses were identified by marital status and/or similar address. We did not concentrate on diagnoses in this group and therefore some of the spouses can have a diagnosis of COPD (and will in that case also be part of the COPD patient-group). Including or excluding spouses with a diagnosis of COPD will in either case tend to bias the results; we have thus decided to include all spouses irrespective of diagnoses to reflect a “real life” situation. Data processing on spouses and identification of a random spouse control group matched by age, gender and socio-demographic status, was similar to data processing for patients.

Patients and matched control subjects were followed through the entire time period or until they died. If diagnosis of COPD of any given individual was made in the first year (1998) we were able to follow that individual 11 years forward in time to see what happened after diagnosis. If a diagnosis of COPD of any given individual was made in the last year (2010) we were able to follow that individual 11 years backwards in time. If a diagnosis of COPD of any given individual was made between the first and the last year we were able to follow that individual both backwards and forward in time.

Municipal services such as care of the elderly (home care nursing and general home care) and municipal rehabilitation is not included as they are paid by the municipals. At present it is not possible to retrieve these data from any register.

The economic consequences of COPD were estimated by determining the annual costs per patient diagnosed with COPD and comparing these figures with the healthcare costs in a matched control group. Diagnosis of COPD is presented to the NPR using information from public and private hospitals. These diagnoses rely on clinical information and results of diagnostic procedures (e.g. spirometry, bronchoscopy). The procedures are registered but the results of the diagnostic procedure are not recorded in the NPR. The health cost was then divided into annual direct and indirect healthcare costs.

Direct costs included the average national costs of hospitalization and outpatient treatment weighted by use, for separate diagnosis-related groups, and specific outpatient costs. These costs were all calculated from Danish Ministry of Health data using diagnose related groups (DRG) and are average case-mix costs of hospitals or outpatient costs updated on a yearly basis. The use and costs of drugs were obtained from the Danish Health and Medicines Agency consisting of the retail price of each drug (including dispensing costs) multiplied by the number of transactions. The frequencies and costs of consultations with general practitioners and other specialists were based on National Health Security data.

Indirect costs included those related to reduced unemployment benefits and to social transfer payments. In Denmark, social transfer payments comprise income derived from state coffers. These payments include subsistence allowances, pensions, social security, social assistance, publicly funded personal support for education, and others. Indirect costs were based on income figures from Income Statistics. Costs were measured on a yearly basis and adjusted to 2010 prices using statistic Denmark's general price index for all costs. All costs were measured in DKK and converted to Euros (€1: DKK 7.45).

Cost-of-illness studies measure the economic burden resulting from disease and illness across a defined population, and include direct and indirect costs. Direct costs are the value of resources used in the treatment, care, and rehabilitation of people with the condition under study. Indirect costs represent the value of economic resources lost because of disease-related work disability or premature mortality. As patients leave the national data registers at the time of death, the indirect costs estimate comprises only the production loss related to disease-related work disability. It is important to distinguish costs from monetary transfer payments such as disability and welfare payments. These payments represent a transfer of purchasing power to the recipients from the general taxpayers but do not represent net increases in the use of resources and, therefore, are not included in the total cost estimate.

Statistical analysis

The study was approved by the Danish Data Protection Agency. Data were anonymised and neither individual consent nor ethical approval was required.

The results are presented as means because some patients had a very high resource consumption which, despite leading to a skewed distribution, would not be adequately represented if data were presented as median values. Extreme values were manually validated and no errors were identified. Statistical analysis was performed using SAS 9.1.3 (SAS, Inc., Cary, NC). ­Statistical significance of the cost estimates was assessed by nonparametric bootstrap analysis (23, 24).

Results

We identified and extracted 171,557 patients with COPD and 86,260 spouses from the national databases (1998–2010) as well as 664,821 randomly selected and matched controls for the patients and 346,524 for the spouses, respectively. The gender and age distribution is shown in Table 1. There is a little more female than male COPD patients—probably because of the age distribution. As expected, most of the patients with an initial diagnosis of COPD are middle-aged or older.

Table 1.  Distribution of age and gender in patients with COPD and controls

Gender	COPD	%-Percentage	Controls	%-Percentage
Male	83,338	49	322,233	49
Female	88,219	51	342,588	51
Age distribution
<20	2,269	1	9,070	1
20–29	621	0	2,483	0
30–39	2,469	1	9,870	1
40–49	8,371	5	33,336	5
50–59	22,215	13	87,977	13
60–69	41,906	24	163,867	25
70–79	57,868	34	221,508	33
≥80	35,838	21	136,710	21
Total	171,557	100	664,821	100
Married or co-habiting (Spouses):	86,260 – 50,3		346,524 – 52,1

The annual average health costs and income of COPD patients before and after diagnosis compared with controls are displayed in Table 2. COPD is associated with significantly higher rates of health-related costs, medication use and lower income rates compared to controls both before and increasingly so after diagnosis.

Table 2.  Health costs and income of COPD patients before and after diagnosis compared with controls

		COPD	Control	P-value
Before	N	859.641	3.290.867
	Outpatient treatment	€ 334	228	<0,01
	Inpatient treatment	€ 1.588	940	<0,01
	Medication	€ 913	436	<0,01
	Public health insurance	€ 359	281	<0,01
	Income from employment	€ 7.443	12.253	<0,01
	Public transfer income total	€ 12.968	11.082	<0,01
	Pension	€ 7.637	7.402	<0,01
	Other public transfers	€ 4.972	3.462	<0,01
	Sickpay (public funded)	€ 359	218	<0,01
	Direct health costs	€ 3.194	1.885
	Indirect costs, foregone earnings	€ 4.810
	Sum of direct and indirect costs	€ 8.004	1.885
	Net costs	€ 6.119
	Social transfer payments	€ 12.968	11.082
	Net costs including transfers	€ 8.006
After	N	764.102	3.934.614
	Outpatient treatment	€ 744	405	<0,01
	Inpatient treatment	€ 5.503	1.783	<0,01
	Medication	€ 1.700	603	<0,01
	Public health insurance	€ 505	360	<0,01
	Income from employment	€ 4.214	7.321	<0,01
	Public transfer income total	€ 13.523	12.871	<0,01
	Pension	€ 9.276	10.606	<0,01
	Other public transfers	€ 3.916	2.112	<0,01
	Sickpay (public funded)	€ 331	153	<0,01
	Direct health costs	€ 8.452	3.151
	Indirect costs, foregone earnings	€ 3.107
	Sum of direct and indirect costs	€ 11.558	3.151
	Net costs	€ 8.408
	Social transfer payments	€ 13.523	12.871
	Net costs including transfers	€ 9.060

(Yearly costs calculated as the average costs with respect to income per year. N = summarized number of individuals × years observed. P-value from bootstrapped t-test. The values given are in Euros).

Figure 1 displays total health costs of COPD and controls distributed by age and gender, showing significantly higher rates of health expenses for COPD for all ages and both genders compared to controls but without major differences between genders in the COPD group.

Figure 1. Health costs of COPD and controls in Euros distributed by age and gender.

Figure 2 shows the income from employment and the public transfer income for COPD patients and controls distributed by age and gender. For both genders COPD was associated with significantly higher rates of public transfer income and significantly lower income from employment until reaching retirement age (65 years). A significant difference in income level was seen between gender as males with COPD and controls had the highest income while no major difference in public transfer income was observed.

The percentage of spouses (after diagnosis) and controls receiving various health care and income is shown in Table 3. Being a spouse was associated with significantly higher rates of health-related contacts, use of more medication, having more persons on various public transfer incomes and less people earning income from employment compared to controls.

Table 3.  Percentage of spouses of COPD patients (after diagnosis) and controls receiving various health care services and income

		Share
		Spouses	Control	P-value
Outpatient treatment	%	37.3	34.8	<0.01
Inpatient treatment	%	17.4	16.1	<0.01
Medication	%	86.8	84.5	<0.01
Public health insurance	%	97.4	96.8	<0.01
Income from employment	%	36.9	37.5	<0.01
Public transfer income total	%	73.1	71.2	<0.01
Pension	%	46.7	47.1	<0.01
Other public transfers	%	22.5	20.8	<0.01
Sickpay (publicly funded)	%	6.6	5.7	<0.01

Bootstrapped Cochran-Armitage test showing whether the fraction received is significant, for each expense type. The values are given in percentages.

The annual average health costs and income of spouses before and after diagnosis compared with controls are displayed in Table 4. Being a spouse was associated with significantly higher rates of health-related costs, medication use and lower income rates compared to controls both before and after diagnosis.

Table 4.  Health costs and income of spouses of COPD-patients before and after diagnosis compared with controls

			Spouses	Control	P-value
Before	N	N	484,247	1,931,058
	Outpatient treatment	€	294	277	≤0.01
	Inpatient treatment	€	1,424	1,271	≤0.01
	Medication	€	531	456	≤0.01
	Public health insurance	€	295	284	≤0.01
	Income from employment	€	12,067	14,992	≤0.01
	Public transfer income total	€	9,822	8,780
	Pension	€	5,246	4,987	≤0.01
	Other public transfers	€	4,256	3,518	≤0.01
	Sickpay (publicly funded)	€	320	274	≤0.01
	Direct health costs	€	2,545	2,287
	Indirect costs, foregone earnings	€	2,924
	Sum of direct and indirect costs	€	5,469	2,287
	Net costs	€	3,182
	Social transfer payments	€	9,822	8,780
	Net costs including transfers	€	4,223
After	N	N	377,154	1,966,359
	Outpatient treatment	€	433	400	≤0.01
	Inpatient treatment	€	1,712	1,475	≤0.01
	Medication	€	633	548	≤0.01
	Public health insurance	€	360	349	≤0.01
	Income from employment	€	9,458	10,912	≤0.01
	Public transfer income total	€	11,158	10.413
	Pension	€	7,338	7.589	≤0.01
	Other public transfers	€	3,523	2.605	≤0.01
	Sickpay (publicly funded)	€	297	219	≤0.01
	Direct health costs	€	3,138	2.772
	Indirect costs, foregone earnings	€	1,454
	Sum of direct and indirect costs	€	4,592	2.772
	Net costs	€	1,820
	Social transfer payments	€	11,158	10.413
	Net costs including transfers	€	2,565

(Yearly costs calculated as the average cost with respect to income per year. N = summarized number of individuals × years observed. P-value from ­bootstrapped t-test. The values given are in Euros).

Figure 3 shows total health expenses, income from employment and public transfer income of spouses before and after diagnosis of COPD compared with controls. For the majority of observation years the total health expenses and the public transfer income were significantly higher, and the income from employment, significantly lower, for spouses. This difference diminishes/disappears over time due to people getting older (and retiring from work).

Figure 2a. Income from employment of COPD patients and controls in Euros distributed by age and gender.

Figure 2b. Public transfer income from employment of COPD patients and controls in Euros distributed by age and gender.

Figure 3. Total health expenses, income from employment and public transfer income in Euros of spouses before and after diagnosis of COPD (green) compared with controls (blue).

In Figure 3 the x-axis begins at minus 11 and stops at 11 years. In year zero all cases and their controls are present. When moving backwards from zero to minus 11, every year will hold less and less cases (and controls) because the spouses of the ones diagnosed with COPD in 1998 were not followed backwards in time, the spouses of the ones diagnosed with COPD in 1999 were only followed backwards 1 year in time and so on. The same is true when moving forwards from year zero to year 11 because the spouses of the ones diagnosed with COPD in 2010 were not followed ­forward in time, the spouses of the ones diagnosed with COPD in 2009 were only followed forward 1 year in time and so on.

One should be cautious to compare one year with another in the figures, because two neighbor years will not be identical but are composed of some identical cases and some cases that differs completely.

As an example: At year minus 11 the spouses of the cases diagnosed with COPD in 2010 are shown (thus we are 11 years before the time of the diagnosis). Year minus 10 hold the spouses of the cases diagnosed in 2010 plus the spouses of the cases diagnosed in 2009 (thus we are 10 years before the time of the diagnosis).

Discussion

To our knowledge, this epidemiological study of COPD is the first to evaluate direct and indirect costs of spouses of COPD patients at a national level. The 12 year time-window gives a unique possibility to look backwards and forwards from the point of initial ­diagnosis.

Including every person at a national level with a first time diagnosis of COPD, their spouses and randomly selected controls matched for age, gender, residence, and marital status provides a large number of persons and data and this makes the direct and indirect costs results more complete and robust.

The study has provided several information of interest:

Being a spouse of a COPD patient was associated with significantly higher rates of health-related contacts, medication use and higher socioeconomic costs. The employment rates and the income rates of employed spouses of COPD patients were significantly lower compared to controls.

These differences were present even 11 years before the partners were diagnosed with COPD for the first time. This might be partly explained by smoking (and the comorbidities that follows) and an unknown number of cases with COPD among the spouses which off course represents an important bias. However, other contributory factors such as educational level, possible anxiety/worrying, loss of workdays/only able to work part-time could play a role. Unfortunately education level is not extracted for the spouses.

The annual net costs of spouses, including social transfers were €4,223 before and 2,565 after the initial diagnosis of COPD patients. This reduction of annual net costs over time is most likely explained by people getting older and retiring from work thus minimizing the differences in income from employment. For all ages and both genders COPD was associated with significantly higher rates of health-related costs and public transfer income and significantly lower income from employment until retirement age (65 years) compared to the controls.

Determining the economic consequences of COPD is complex. With an accurate diagnosis and appropriate treatment patients’ risk of exacerbation decreases as well as the associated costs and maybe even death (although still controversial). In addition quality of life improves. On the other hand the diagnostic procedures, treatment and management of COPD add to the direct costs. However, even when we include the costs associated with the diagnosis and treatment of COPD, our study showed that patients with COPD incur a significant economic burden because the lower employment rates and the lower income rates of employed COPD patients exceed the direct costs of the disease. These factors influence costs and should be included in the disease burden. As epidemiological this study is solely based on national databases leading to some limitations.

The results do not reflect the impact of COPD per se as the pronounced comorbidity of COPD patients (depression, anxiety, cardiovascular disease etc.) will have an impact, too. By adjusting for the above mentioned available factors we have tried to minimize this effect. Ideally, we would have adjusted for smoking status but this information is not registered in any of the national databases in Denmark. The lack of smoking status clearly introduces an important bias as this can account for a substantial part of the observed difference in the groups.

Information about educational level was present, but in the end we decided not to use this matching parameter. On one hand educational data are very reliable; for everyone between the ages of 14 and 80 where only little information is lacking. On the other hand there is no available information about educational level for people under the age of 14 years and for a very large proportion of those aged 80 years or more – the latter due to lack of registration of education in the Danish Civil ­Registration System database. This registration, based on information from the different teaching institutions, did not begin until 1970.

We cannot tell the educational level of these unregistered persons and the problem is the same for both COPD and controls. Furthermore this matching criteria left us no other choice than using only one matched ­control for each COPD patient because it was not possible to find more in the periphery of Denmark, thus reducing the included amount of patients by approx. 1/4 (from 171,557 to 131,811). After having tried both methods (4 matched controls (excluding education as a matching parameter) per patient and including education as a factor matching cases and controls 1:1) and evaluated the results of both approaches we decided to exclude education level as a matching parameter because it did not change the results substantially and therefore we wanted to exclude as few as possibly to make the study “true” national/realistic.

In Denmark, ICD-10 classification is only used in the secondary health care sector (hospitals), not in the primary health care sector (general practitioners). Even though this study spans 12 years and includes all with an initial primary or secondary ICD-10 diagnosis of COPD and the majority of known COPD patients are believed to be included over time there is a risk of underestimation. COPD patients that are only followed in the primary health sector during the study period are not included and this will bias the results as these patients will tend to be less sick.

The accuracy of the diagnosis and management is sensitive to the diagnostic criteria used. The people aged below 30–40 years with a diagnosis of COPD may – at least to some extent - be due to misclassification. As this is a nationwide epidemiological study we decided not to exclude anyone because of age as we do not know who had been rightly or wrongly classified as having COPD and because the extracted data regarding age and gender seemed to fit well for every observed age group with no obvious outliers.

Furthermore, although J44 by far is the most common diagnosis used in COPD, several different diagnoses deriving from J40 (bronchitis), J41 (simple and mucopurulent chronic bronchitis), J43 (emphysema) and J47 bronchiectasis) are also used to some (unknown) extent. We have chosen to exclude these diagnoses. By allowing both primary and secondary diagnosis of COPD some correction of this problem has taken place but may have opened up for adding further comorbidity. In the control group there will be a number of undiagnosed patients with COPD (approx. 10%) thus introducing a bias tending to reduce the difference in cost between the two groups in our study (25).

Conclusion

This study contributes with knowledge of the economic and health related consequences for the COPD patients and their spouses. For COPD showing substantially impact on income level regardless of age and gender, patients earning approximately half of that of controls before diagnosis. After diagnosis this effect diminishes due to people getting older and retiring from work. Overall total health expenses are more than twice as high in the COPD group regardless of age and gender compared to controls. The gap in health expenses between the two groups are increasing with age until the age of 80 where the difference is getting less, presumably because of an increase in comorbidity in controls.

Furthermore for the first time spouses of COPD patients has been included in an economic evaluation, showing significantly higher rates of health-related contacts, medication use and higher socioeconomic costs compared t o controls as well as significantly lower employment and income rates.

As the economic consequences are present years prior to the first primary or secondary diagnosis of COPD in the secondary health sector, it could be speculated that early identification and intervention might be part of the solution.

Adequate treatment may reduce the consequences of COPD but, if socially and economically significant reductions in morbidity, mortality and social impact are to be achieved, much earlier disease identification and management is needed. More research and evaluation of case finding strategies and disease management programs are needed (26).

Declaration of Interest Statement

This study was supported by an unrestricted grant from the Respironics Foundation and from a grant from Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen. The study is a part of a larger study supported by the Center of Healthy Aging, Faculty of Health Sciences, University of Copenhagen, with the purpose of identifying the burden of chronic diseases. None of the funders had any influence on the study design, the collection, analysis and interpretation of the data, the writing of the report, or the decision to submit the paper for publication. The study was approved by the Danish Data Protection Agency. Because data handling was anonymous, individual and ethical approval was not mandatory.

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper: Anders Løkke: Planning, Statistics, Writing and Discussion; Ole Hilberg: Planning, Writing and Discussion; Jakob Kjellberg: Planning, Statistics and Writing; Rikke Ibsen: Statistics and Writing; Poul ­Jennum: Planning, Writing and Discussion.