Economics of COPD: literature review and experiences from field work

Transcription

1 The Clinical Respiratory Journal ORIGINAL ARTICLE Economics of COPD: literature review and experiences from field work R. Nielsen, M. Klemmetsby and A. Gulsvik Department of Thoracic Medicine, Institute of Medicine, University of Bergen, Norway Abstract Introduction: The burden of diseases should be described in terms of costs. The available literature gives imprecise estimates of costs of chronic obstructive pulmonary disease (COPD) in the Nordic populations. Previous studies have methodological weaknesses related to choice of disease criteria, the use of highly selected populations and insufficient specification of the cost process. There are no robust estimates concerning the economics of COPD in Norway. Methods: Wehaveconducteda1yearfollow-up cost of illness study in a general population, recruiting eversmoking Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 2+ COPD patients and eversmokers without COPD. We have used diaries to recollect data, and comprehensive questionnaires to cover all costs of COPD. Results: The main challenges were the participants unwillingness to complete diaries, the large amount of information and the logistics related to following up 476 individuals on four occasions during one year. Conclusions: We doubt the effect of diaries. However, we recommend a detailed planning of logistics and to emphasize main cost drivers. Please cite this paper as: Nielsen R, Klemmetsby M and Gulsvik A. Economics of COPD: literature review and experiences from field work. The Clinical Respiratory Journal 2008; 2: Key words COPD cost of illness diaries general population GOLD literature search Norway Correspondence Rune Nielsen, MD, Lungeavdelingen, Haukeland University Hospital, N-5021 Bergen, Norway. Tel: Fax: rune.nielsen@med.uib.no Accepted: 28 March 2008 DOI: /j X x Ethics The study was approved by the Regional Committee for Medical Research Ethics of Western Norway (REK-Vest, Bergen). All participants received face-to-face information as well as written information, and provided written informed consent Conflicts of interest The authors have declared that they have no conflicts of interest. Introduction The burden of diseases should be known to health care providers, and this enables health authorities to improve the allocation of resources. Costs are a readily available marker of burden of disease. In Norway, 7.0% of the adult population (26 82 years) have Global Initiative for Chronic Obstructive Lung Disease (GOLD)-defined chronic obstructive pulmonary disease (COPD) (1). The only available Norwegian cost of COPD estimate amounts to NOK per patient per year (2).This estimate comes from 27 COPD patients recruited to a costeffectiveness study in a hospital outpatient clinic. A criterion for FEV1/FVC to diagnose COPD was not given, but FEV 1 % predicted had to be 40% 80%. The main objectives of the present paper were to review available literature on the economic burden of COPD, to present the field work of a population-based economic study of COPD in Bergen, Norway called EconCOPD and to describe the challenges of this study. Literature review Studies dedicated to calculating the burden to society of particular problems are called Cost of Illness (COI) studies(3). Costs are divided into direct costs (related to treatment), indirect costs (production loss) and intangible costs (pain, grief). A (period) prevalencebased approach describes costs in a pre-defined period. An incidence-based approach traces costs throughout 104 The Clinical Respiratory Journal (2008) ISSN

2 Nielsen et al. COPD cost studies the entire disease process (to remission or death). The data can be gathered retrospectively or prospectively. By using register data, one can gather costs from a top-down perspective. A bottom-up perspective implies gathering data from the individual s point of view. Cost per patient or group are given as attributed costs or excess costs when comparing to a person or group without the disease. The latter approach thus includes costs of co-morbidities associated with the index diseases. Variation of costs should be expressed with sensitivity analyses. One varies, in a standardised way, the conditions determining the cost estimates e.g. unit costs, utilisation of health care services and prevalence of disease. A search in PubMed ( ), combining medical subject headings COPD and health care economics and organizations, yielded 718 publications. The 718 abstracts were screened for estimates of total COPD costs in general populations. This resulted in 70 papers being read in-depth. Excluded were reviews (22), papers reporting only costs of risk factors or exacerbations (21), papers with selected populations (9) and papers not peer reviewed (3). One publication from Norway was kept for comparative reasons (2). The final 15 reviewed papers are all published between 1999 and 2007 (Table 1). There are several recommendations from health economists (3) that are rarely met in publications on costs of COPD. First, the valuation of unit costs is rarely questioned. Second, few authors state the problems of capital costs. Finally, the sensitivity analyses are not performed as recommended. The importance of different costing of units is exampled by the difference between Wards (4) USD 6.6 billion estimate and Wilsons (5) USD 14.5 billion estimate. A hospital stay in the latter study has a unit cost of >USD 5000, whereas in the former, a hospital stay costs slightly less than USD Concerns regarding the costing process also applies to the estimates from the population-based Nippon COPD Epidemiology survey in Japan (6). They used hospitalisation data only for patients above 70 years of age, resulting in an average length of stay of 22.5 days, which will give an overestimation of hospital costs for all ages. Diagnosis based top-down register studies (4 9) generally include a limited number of costs, and ignores underdiagnosis of disease and the possibility of non-costing observed COPD patients. Communitybased studies relying on self-reported diagnoses (10, 11) and symptoms (12) face the same uncertainty regarding validity of the diagnoses and cost data. The Confronting COPD study (12) include only households with a COPD patient recruited through a telephone response. One may question the representativeness of the sample. In this review, only 5 of 15 studies have conducted spirometries (2, 6, 13 15), and only two of these studies are from true populationbased samples (6, 14). Many studies, aiming to describe the general population are from more or less selected populations as general practitioners or specialist practices (13, 16) or health maintenance organisations (15, 17). The OLIN study from Northern Sweden (14) aimed to include all COPD cases in a general population using defined spirometry criteria. The average COPD cost per patient was estimated to SEK. However, a post bronchodilator spirometry is not performed to exclude overt asthma patients. Estimates are only given as COPD attributable costs. Larger estimates are found in the United States using the excess cost approach (10), where total costs in COPD patients are compared with total costs in non-copd persons. In the Swedish study, costs for deaths, pulmonary rehabilitation, complementary medicine or help from family and friends related to COPD are not reported. Summarising this literature review, we favour the study design of OLIN (14). However, in a Nordic setting, there is need of economic studies applying post- bronchodilator spirometry and estimating excess costs caused by COPD in a general population. Furthermore, a large study would give precise estimates in gender and age groups. Field work We conducted between March 2005 and July 2006 a one year follow-up study of smokers with spirometrically defined COPD and smokers without COPD. The aim was to describe the attributable and excess costs of COPD in Norway using valid economic methods in a general population. Study sample All participants had to be 40 years or older and were eversmokers of at least 2.5 pack years. COPD-patients were subjects with post-bronchodilator FEV 1 /FVC <0.7 and FEV 1 <80% of predicted values (18). Control subjects were eversmokers with FEV 1 /FVC 0.7 and FEV 1 80% of predicted values. Participants were recruited from the Hordaland County Respiratory Health Survey (HCRHS), a representative cohort of the general Norwegian population first examined in 1985 (1). This population was re-examined in , and all COPDpatients (n = 111) and randomly selected control The Clinical Respiratory Journal (2008) ISSN

3 COPD cost studies Nielsen et al. Table 1. Publications giving estimates of cost of illness of COPD First author, year of publication, country and reference Inclusion criteria Population N Design Costs included Results and year of study Comments Bilde 2007, Denmark (7) Hospitalised for COPD (ICD-10: emphysema (J 43.x), chr bronchitis (J42.9) or unspec airways obstruction (J 44.x)) last 5 years. Age 40. General population Top-down, prevalence Hospitalisations and primary care contacts. Not drugs, home oxygen Year 2002 Excess costs DKK per Total excess costs: DKK 1.9 billions Narrow inclusion criteria, not comprehensive cost gathering. No Miller 2005, USA (10) Self reported COPD, Chronic Bronchitis or emphysema. General population; stratified (socioeconomically, geographically), clustered (households), multistage sample Cases: 144 Controls: 8150 Bottom up, prevalence based, prospectively (1 year, 4 interviews) Direct medical, not including OTC medication and home oxygen treatment Year 2000 Excess costs: USD per Attributable costs: USD per Narrow inclusion criteria not including undiagnosed and non-costing subjects. No Mapel 2005, USA (15) ICD9 chr bronchitis (491.x), emphysema (492.x) or chronic airways obstruction (496) at two outpatient visits or one hospitalisation the year preceding the study. Age >40 years. HMO Bottom up, prev based, retrospective Direct medical Year 1999 Total costs for patients (irrespective cause): Men USD per Women USD per No attribution of costs. Excludes deceased. Izguierdo-Alonso 2004, Spain (16) Nishimura 2004, Japan (6) Doctors diagnosis of COPD (not defined) and FEV1/FVC < 0.7 FEV1/FVC < 0.7, age 40 years GP and specialist practices COPD prevalence from general population, utilisation from literature review 560 Bottom up, prevalence Direct medical Year 2000 Mean direct medical costs per Direct medical and indirect (productivity losses). Year 2000 USD 1220 (indirect USD 262), per Narrow inclusion criteria diseased population, not including noncosting subjects. No Unit costs and use of health care from other publications. Some estimates that seem nonapplicable to the general population. Wouters 2003, Canada, France, Italy, The Netherlands, Spain, UK, USA (12) Self reported COPD, emphysema or chronic bronchitis, or symptoms of chr bronchitis. Age >45 years, 10 packyrs of tobacco exposure. General population Bottom up, prevalence Direct medical and indirect costs Year 1999 Attributable costs range USD in PPP per Not including undiagnosed subjects, no spirometric validation of diagnosis. Large time span to be recapitulated. No Miravitlles 2003 Spain (13) COPD: FEV1/FVC < 0.7 and FEV1 < 80% of predicted, and sought attention from GP due to exacerbation From GP practices 766 Bottom up, prevalence based, prospective (1 year, 2 interviews) Direct medical costs Year 1998 Attributable USD per Patients all have had exacerbations, only included from GP practice. High withdrawal numbers. No information about bronchodilatation. 106 The Clinical Respiratory Journal (2008) ISSN

4 Nielsen et al. COPD cost studies Gallefoss 2002, Norway, (2) Doctors defined COPD with FEV % of predicted values Hospital outpatient clinic 27 Cost of effectiveness analysis. Direct medical costs and indirect cost. Year 1995 Attributable costs NOK per >From control group in a CEA on a selfmanagement program. Weak estimate due to low number of participants and inclusion criteria. Jansson 2002, Sweden (14) COPD: FEV1/FVC < 0.7 General population, 7 birth cohorts: , , , , , , Bottom up, prevalence based, prospective (1 year, 4 interviews) Comprehensive direct and indirect costs Year 1999 Attributable costs SEK (indirect costs 7828) per National level: 9.1 billion SEK No bronchodilatation, only 7 birth years represented. Strassels 2001, USA (11) Self reported COPD, chronic bronchitis or emphysema, age 40 years. General population; stratified, clustered multistage sample 228 Bottom up, prevalence based, prospectively (1 year, 4 interviews) Direct medical costs Year 1987 Total medical costs for patients were USD per, whereof 25.3% was COPDattributable. Narrow inclusion criteria not including undiagnosed and non-costing subjects. Outdated estimates. No Jacobson 2000 Sweden (8) ICD9-codes: Asthma (493), bronchitis (490, 491), emphysema (492), chronic airway obstruction (496) Aims to describe the general population using national registries and previous publications. Direct and indirect costs Year 1991 National level: Direct costs 1085 mill SEK, indirect costs 1699 mill SEK Not including undiagnosed subjects. Dependent on registries for all utilisation and unit costs, some of which have obvious weaknesses. No Mapel 2000, USA (17) Patients billed with ICD codes: chronic bronchitis (491.x), emphysema (492.x) and chronic airway obstruction (496). Age 30 years HMO cases controls Bottom up, prevalence Direct costs hospitalisations, outpatient clinics, medication Year 1997 Excess costs: USD per Diseased population undiagnosed not included, non-costing not included. No Ward 2000, USA (4) ICD codes: chronic bronchitis, chronic bronchitis (491.x), emphysema (492.x) and chronic airway obstruction (496). Age 45 years. The general population. Use national surveys, and previous US publications on utilisation of health care resources Direct costs Year 1994 Total nationwide costs USD 6.6 billion Undiagnosed not included. No Wilson 2000, USA (5) ICD codes chronic bronchitis and emphysema Aims to describe the general population using national surveys, and previous publications. Direct costs Year 1996 Attributable costs: 896 USD per Total nationwide costs USD 14,6 billion Undiagnosed not included. No Rutten-van Mölken 1999, Netherlands (9) Varies according to levels of specificity in the various registers used. Aims to describe the general population using national registries Direct costs Year 1993 Attributable costs USD 813 per Lack of distinction between asthma and COPD in obtaining some of the utilisation estimates (primary care services and medication). No NA, not applicable; NR, not reported; PPP, purchasing power parity; HMO, Health Maintenance Organization; excess costs, total costs for cases subtracted total costs for controls; attributable costs, costs specific for index diseases (COPD); total costs, costs irrespective of cause; GP, general practitioner. The Clinical Respiratory Journal (2008) ISSN

5 COPD cost studies Nielsen et al. Figure 1. Flow chart describing the design and follow-up of subjects in the economic study of COPD in Bergen, Norway. Stapled lines represent subjects lost because of deaths. Solid lines represent subjects lost because of other reasons. HCRHS, Hordaland County Respiratory Health Study. HUH, Haukeland University Hospital. subjects (n = 149) were invited to participate in EconCOPD (Fig. 1). From the Haukeland University Hospital (HUH), COPD registry with 2735 patients, 500 subjects were randomly selected. This increased the precision of estimates of costs in severe COPD, as the severe cases are rare in a general population. However, 24 COPD patients were excluded because of death prior to invitation, 140 because of long travelling distance and 10 because of previous participation in a pilot study (Fig. 1). Data collection A group of 5 physicians in pulmonary medicine and 2 health economists developed two cost questionnaires for baseline and follow-up studies, respectively. Both questionnaires used several questions modified from the OLIN COI study (19). We added questions regarding smoking habits, education and respiratory symptoms from the HCRHS questionnaire (20). Quality of life (QoL) was recorded using EQ-5D and EQ-VAS (21). The questionnaires were tested in a pilot study on 29 participants from The Haukeland University Hospital COPD registry. All interviewers were trained using written guidelines. All subjects who accepted the invitation were investigated at the outpatient clinic Department of Thoracic Medicine, HUH. A post bronchodilatation spirometry and a baseline interview were performed. The baseline interview reviewed demographical data, airway symptoms, exacerbation of obstructive lung disease, co-morbid conditions, use of health care resources, productivity losses and QoL. Quantitation of utilisation was done with reference to the last three months. There were 80 main questions and 269 specified questions. Forms not completed at the outpatient clinic, were thereafter completed by phone. 108 The Clinical Respiratory Journal (2008) ISSN

6 Nielsen et al. COPD cost studies All patients received 13 diaries each covering 4 weeks. The diaries contained 4 sections including respiratory symptoms, health care utilisation, productivity losses and QoL. The first three parts were to be filled out when events occurred. The last section was to be completed weekly. Subjects received face-toface instructions on how to fill out the diaries. A precompleted example diary was distributed. Subjects were encouraged to contact the project nurse by phone whenever they had questions concerning the completion of the diaries. All participants were interviewed by telephone every 12th week (though the last interval was 16 weeks). The follow-up interviews emphasized changes in respiratory symptoms defining exacerbations, health care utilisation and costs, and QoL. During these 4 interviews, 195 main questions were asked, with 585 specified questions. All interviewers conducted at least 2 supervised interviews on non-included volunteer COPD-patients. The training program included lectures on the pathogenesis, epidemiology and clinical features of COPD. The project physician recruited and informed all participants. The chief bioengineer conducted quality controls of the spirometers. One registered nurse with extensive clinical experience and seven medical students conducted the interviews. The nurse and a physician supervised all follow-ups. All completed questionnaires were quality controlled. Results Ninety COPD patients from the HCRHS were included (81%) (Fig. 1). Ten declined because of disease (9%). From the hospital registry altogether, 326 subjects were invited and 250 patients were included (77%) at the baseline interview. The most frequent reason to decline among both groups was disease (9% and 7%, respectively). Of the 149 invited control subjects, 136 completed the baseline interview (91%). Four percent of control subjects would not participate because of an unacceptable workload. During the follow-up period, 15 patients died (2 from the HCRHS (2%), and 13 from the HUH COPD Registry (5%)). Forty-one subjects (9%) withdrew 7 patients from the HCRHS, 30 from the hospital registry and 4 control subjects. The overall main reasons for withdrawal during follow-up were disease (34%) and an unacceptable workload (22%). Sixteen participants (39%) gave no reason to withdrawal. Among subjects withdrawing because of disease, the largest group was age frailty, neurological disease and dementia (6 out of 14), while 4 individuals gave cardiopulmonary diseases as reason to withdrawal. Most withdrawals occurred immediately after the baseline interview (Fig. 1). Fiftyeight participants refused to complete diaries. Two hundred and six participants completed more than 6 out of 13 diaries. Discussion Comprehensiveness Among items included were details as help from friends and family and use of alternative care, as well as hospitalisations, drug use and health care provider visits. In a population of COPD patients, this demand for information poses a considerable risk of fatigue, and thus withdrawals from the study. To ease recollection of complex drug information, all patients brought prescription drugs with them to the baseline interview, and they were instructed to bring their medication to the phone. The patients found it difficult to estimate their utilisation of resources and the frequency and increase in severity of symptoms. The interviewers were instructed to encourage the subjects to give their best guess, and to explain the questions when necessary. Written instructions were given to all interviewers. Diaries In spite of extensive training and advices during the survey, several participants found the diaries inconvenient. Some participants had poor eyesight and impaired hand writing. Subjects wanting to abstain from completing diaries were granted this. The timing of follow-up interviews It was difficult to keep the schedules during Christmas and Easter. Postponements were up to 4 weeks. This necessitated strict information concerning what period of time each interview covered. When the aberrancy from the planned interview was less than 2 weeks and the participant had used the diaries, the diary period was followed. When the postponement was longer than 2 weeks, or the patient did not use the diaries, the interview strictly covered the exact period of time since the previous interview. We used several phone numbers for each patient. Some were contacted as many as thirty times to complete an interview. Conclusion EconCOPD s main strengths are recruiting patients from a general population and identifying patients by The Clinical Respiratory Journal (2008) ISSN

7 COPD cost studies Nielsen et al. using post bronchodilatation spirometry criteria. The precision of cost estimates in the low prevalent severe stages of COPD was increased by including participants from a hospital population. Inclusion of control subjects enabled calculation of excess costs, thus revealing costs incurred by co-morbid conditions. To our knowledge, this is the only COI study so far including both costs from pulmonary rehabilitation, home oxygen treatment and COPD deaths. All interviewers went through standardised training, and they were instructed to avoid recall bias. The number of interviewers will ensure that we are not vulnerable to individual style in conducting interviews. Diaries might have been less comprehensive, and incentives could have motivated participants to a better adherence to the protocol. Emphasizing main cost drivers as hospitalisation, office visits and sick leave might have captured the major parts of costs of COPD. However, given the lack of previous studies on costs of COPD in Norway, as well as the lack of detailed information on COPD treatment in Norway, we chose to focus on a comprehensive cost gathering. This will give us data on which items are major and which are minor cost drivers. Acknowledgement Funded by The Norwegian Association of Heart and Lung Patients and EXTRA funds from the Norwegian Foundation for Health and Rehabilitation. References 1. Johannessen A, Omenaas ER, Bakke PS, Gulsvik A. Implications of reversibility testing on prevalence and risk factors for chronic obstructive pulmonary disease: a community study. Thorax. 2005;60(10): Gallefoss F, Bakke PS. Cost-benefit and cost-effectiveness analysis of self-management in patients with COPD a 1-year follow-up randomized, controlled trial. Respir Med. 2002;96(6): Jefferson T, Demicheli V, Mugford M. Elementary economic evaluation in health care. London: BMJ Publishing Group, Ward MM, Javitz HS, Smith WM, Bakst A. Direct medical cost of chronic obstructive pulmonary disease in the U.S.A. Respir Med. 2000;94(11): Wilson L, Devine EB, So K. Direct medical costs of chronic obstructive pulmonary disease: chronic bronchitis and emphysema. Respir Med. 2000;94(3): Nishimura S, Zaher C. Cost impact of COPD in Japan: opportunities and challenges? Respirology. 2004;9(4): Bilde L, Rud Svenning A, Dollerup J, Baekke Borgeskov H, Lange P. The cost of treating patients with COPD in Denmark a population study of COPD patients compared with non-copd controls. Respir Med. 2007;101(3): Jacobson L, Hertzman P, Lofdahl CG, Skoogh BE, Lindgren B. The economic impact of asthma and chronic obstructive pulmonary disease (COPD) in Sweden in 1980 and Respir Med. 2000;94(3): Rutten-van Molken MP, Postma MJ, Joore MA, Van Genugten ML, Leidl R, Jager JC. Current and future medical costs of asthma and chronic obstructive pulmonary disease in The Netherlands. Respir Med. 1999;93(11): Miller JD, Foster T, Boulanger L, Chace M, Russell MW, Marton JP, Menzin J. Direct costs of COPD in the U.S.: an analysis of Medical Expenditure Panel Survey (MEPS) data. Copd. 2005;2(3): Strassels SA, Smith DH, Sullivan SD, Mahajan PS. The costs of treating COPD in the United States. Chest. 2001;119(2): Wouters EFM. Economic analysis of the confronting COPD survey: an overview of results. Respir Med. 2003;97(Suppl. 3): S Miravitlles M, Murio C, Guerrero T, Gisbert R. Costs of chronic bronchitis and COPD: a 1-year follow-up study. Chest. 2003;123(3): Jansson SA, Andersson F, Borg S, Ericsson A, Jonsson E, Lundback B. Costs of COPD in Sweden according to disease severity. Chest. 2002;122(6): Mapel DW, McMillan GP, Frost FJ, Hurley JS, Picchi MA, Lydick E, Spencer MD. Predicting the costs of managing patients with chronic obstructive pulmonary disease. Respir Med. 2005;99(10): Izquierdo-Alonso JL, de Miguel-Diez J. Economic impact of pulmonary drugs on direct costs of stable chronic obstructive pulmonary disease. COPD. 2004;1(2): Mapel DW, Hurley JS, Frost FJ, Petersen HV, Picchi MA, Coultas DB. Health care utilization in chronic obstructive pulmonary disease. A case-control study in a health maintenance organization. Arch Intern Med. 2000;160(17): Gulsvik A, Tosteson T, Bakke P, Humerfelt S, Weiss ST, Speizer FE. Expiratory and inspiratory forced vital capacity and one-second forced volume in asymptomatic never-smokers in Norway. Clin Physiol. 2001;21(6): Jansson SA. Health Eonomic Epidemiology of Obstructive Airway Diseases The Obstructive Lung Disease in Northern Sweden Studies VII. Stockholm, Karolinska Institutet, Brogger JC, Bakke PS, Gulsvik A. Comparison of respiratory symptoms questionnaires. Int J Tuberc Lung Dis. 2000;4(1): Brooks R. EuroQol: the current state of play. Health Policy. 1996;37(1): The Clinical Respiratory Journal (2008) ISSN