Rheumatic disorders concern a broad spectrum of painful disorders affecting the musculoskeletal system, and are responsible for a considerable amount of disease burden and also a substantial economic burden. This economic burden consists of direct and indirect costs, but also the so-called intangible costs. In this study, we estimated the societal cost of rheumatic disorders in the Netherlands, including intangible costs.
Data from the National Monitor on Musculoskeletal System 2010 were used to assess resource used, multiplied with standard prices for the Netherlands to obtain total costs for the 1.8 million people suffering from rheumatic disorders. These estimates were supplemented with data from secondary sources.
Total societal costs of rheumatic disorders in the Netherlands amount to €4.7 million a year, that is, €2665 per person with rheumatic disorders.
Rheumatic disorders have considerable costs, which justify more attention in discussing investments in facing the challenges in our ageing Western societies.
Introduction
Rheumatism or a rheumatic disorder is a non-specific term used to describe any painful disorder affecting the musculoskeletal system including joints, muscles, connective tissues and soft tissues around the joints and bones. It is also used to describe rheumatic fever affecting heart valves. However, the medical profession uses specific terms to describe rheumatic disorders such as rheumatoid arthritis, ankylosing spondylitis, gout and systemic lupus erythematosus, of which there are more than 100 various clinical types. Despite differences in clinical features, they have in common that they are responsible for a considerable amount of health-care use and disability .
Next to the disease burden, rheumatic disorders represent a substantial economic burden on society. This economic burden can be estimated in a cost-of-illness study by identifying and measuring all costs of a disease. Cost-of-illness studies do not provide information on how rheumatic disorders should be treated, but they can be used for description next to other estimates based on incidence or mortality, for comparisons in time and between countries and projection of future health costs . There are several published cost-of-illness estimates on rheumatic disorders . However, most cost-of-illness studies on rheumatic disorders are restricted to a specific condition, as, for example, rheumatoid arthritis and ankylosing spondylitis . Moreover, usually, cost-of-illness estimates include the direct and indirect costs of a disease. However, it is argued that also costs associated with patient health losses that do not directly translate into health-service use or productivity losses should be incorporated . These so-called intangible costs are costs of the inconvenience and difficulties for the patient, such as pain, anxiety and discomfort. To estimate the intangible costs the use of the willingness-to-pay (WTP) method is proposed.
The aim of this study was to estimate the societal costs of rheumatic disorders in the Netherlands, including the intangible costs.
Material and methods
To assess the costs of rheumatic disorders in the Netherlands from the societal perspective we estimated the direct costs, indirect costs and intangible costs. Direct costs are all health-care costs that are directly related to the treatment of the disease, as, for example, hospital days, consultations with doctors and medication. Indirect costs arise as a secondary result of the disease, such as production losses in paid and unpaid work. Intangible costs are the monetary value of the inconvenience and difficulties due to rheumatic disorders. The costs were expressed in 2011 euro and comprise a 1-year period.
To estimate the direct and indirect costs of rheumatic disorders, data from the National Monitor on Musculoskeletal System 2010 (NMMS-2010) were used . The target population of the NMMS-2010 is the Dutch adult non-institutionalised population. A questionnaire was sent to a random sample of 40 000 household addresses. The persons from these households aged 18 years and older that had their birthday the soonest were asked to complete the questionnaire. The net response percentage was 22.4% ( n = 8904). The questionnaire contained questions on demographic characteristics, societal participation, life style, health and health-care use. The questions concerning health included questions on rheumatic disorders based on the module ‘arthritis’ from the Behavioral Risk Factor Surveillance System (BRFSS), Centers for Disease Control and Prevention (CDC) ( www.cdc.gov ):
- 1.
In the past 12 months, have you had serious pain, aching, stiffness or swelling in or around a joint?
- 2.
Have you ever been told by a doctor that you have arthritis? If so, which form?
Rheumatic disorders were defined as serious complaints (pain, aching, stiffness and/or swelling) in the past 12 months by persons who ever had been told by a doctor to have arthritis. In the NMMS-2010, 18.0% of the respondents reported to ever have been told to have arthritis. Of these respondents, 76.1% indicated to have had serious complaints in or around one or more joints in the past 12 months, which is 13.7% of all respondents. Extrapolated to the Dutch population of 13 million aged ≥18 years , it is estimated that 1.8 million are suffering from rheumatic disorders. Based on the form of rheumatic disease reported, a further categorisation was made in inflammatory rheumatic diseases ( n = 421,000), soft-tissue rheumatic diseases ( n = 242,000) and osteoarthritis ( n = 1,100,000).
Direct costs
Direct costs included in the present study are costs of visits to health-care providers, day treatment, hospitalisation, home care, diagnostics, medicine, aids and devices and surgery.
From the NMMS-2010, data about number of visits to health-care providers in the previous 12 months, number of day treatments and hospitalisations and hours of home care during the previous quarter were retrieved for people without and with rheumatic disorders by disease category (inflammatory rheumatic diseases, soft-tissue rheumatic diseases and osteoarthritis), age and gender. Quarterly data were extrapolated to a 1-year period. The amount of care use was multiplied with standard prices for the Netherlands (see Appendix 1 ) to obtain yearly costs. We assumed that rheumatic complaint-related costs were those costs of health care that exceeded the average costs of health care estimated for the population without rheumatic complaints. Rheumatic disorder-related costs were therefore estimated by the difference in costs per person between people with and without rheumatic disorders for different age categories and gender. Total difference in cost was obtained by multiplying the difference in cost per age category and gender with the number of people with rheumatic complaints in this category.
Rheumatic disorder-related costs of nursing homes and rehabilitation centres, medication, diagnostics and surgery could not be estimated from the NMMS-2010, and were therefore derived from other sources.
Costs of nursing homes and rehabilitation centres were based on the Dutch Cost of Illness Study 2007 ( www.kostenvanziekten.nl ) , a top-down cost-of-illness study in which total health-care costs were divided into specific disease categories, including rheumatoid arthritis, soft-tissue rheumatic diseases and osteoarthritis. Further, costs of medication (both over-the-counter (OTC) and prescription medications) were based on this study.
Costs of diagnostics for inflammatory rheumatic disease were assessed on the basis of the cost-of-illness study in Dutch rheumatoid arthritis patients . Cost estimates of diagnostics for patients with soft-tissue rheumatic diseases and osteoarthritis were not available.
To estimate the costs of surgery, numbers of specific rheumatic surgical operations were obtained from the National Medical Registration 2009 (LMR; www.kiwaprismant.nl ) and multiplied by their standard prices .
Use of aids and devices was retrieved from the NMMS-2010 data. Costs of aids and devices were assessed by averaging the total yearly costs per user with an invoice during that year over the period 2005–2009 ( www.gipdatabank.nl ). For simple aids and devices for mobility, it was assumed that these will last for 7 years on average, and for orthoses, joint protheses and house adaptations this period is assumed to be 15 years on average ( www.gipdatabank.nl ).
Indirect costs
The indirect costs included in this study are the costs of production losses in paid and unpaid work. Number of sick days, occupational disability and hours of unpaid work for persons with and without rheumatic disorders were obtained from the NMMS-2010 data.
We used two methods to estimate the costs of production losses in paid work, the friction cost method and the human capital approach . The friction cost method takes the employer perspective and assumes that within a production process ultimately everybody is replaceable and production losses only occur during the period that is needed to fill up the vacancy. Therefore, only sick days, were taken into account, that occur within the friction period of 22 weeks . For work absence longer than 22 weeks, productivity loss for 22 weeks was counted. Occupational disability does not lead to friction costs, as in the Netherlands people are only declared disabled after at least a year of work absence. The human capital approach takes the employee perspective and values all lost working days due to work absence, occupational disability and lower labour participation (less people with paid jobs and lower number of working hours a week).
Production losses were valued using the gender-specific average hourly wage, taking into account an elasticity of 0.8 between reduced labour time and productivity . This indicates that when people work less they first skip the less valuable activities, so the productivity will decrease less than proportionally. The average hourly productivity loss was €33.32 for men and €26.60 for women . Sick days were assumed to account for 8 h of work lost.
Unpaid work was reported by respondents of the NMMS-2010 in number of hours per day they perform housework and number of hours per week they perform volunteer work. The difference in hours between respondents with and without rheumatic disorders was valued using a price of €12.82 per hour, based on replacement costs for housework .
Intangible costs
Next to direct costs and indirect costs, rheumatic disorders will also result in inconvenience and difficulties for the patient. A method to value this impact in monetary terms is the WTP method . In this method, respondents are asked to indicate what the maximum amount is they are prepared to pay for a (hypothetical) treatment that would cure rheumatic disorders. We performed a WTP study by asking people to indicate how much additional health insurance premium they are willing to pay monthly for including such a treatment in the standard health insurance package in the Netherlands. The current premium for the obligatory basic health-care package is about €100 per month. Nine WTP intervals were shown to the respondents (€0, €1–5, €6–10, €11–20, €21–40, €41–60, €61–80, €81–100 and >€100) and subsequently the exact monthly amount respondents are willing to pay additionally was asked in the chosen interval. Finally, respondents were asked how sure they are that they would really pay this amount (not sure, more or less sure, sure). Respondents who indicated ‘not sure’ were excluded from the analysis .
Next to the WTP method, we used an alternative method to estimate intangible costs. Respondents were asked to indicate their quality of life on the Short Form (12) Health Survey (SF-12) . These scores were translated into a utility score . between ‘0’ and ‘1’, with ‘1’ indicating perfect health and ‘0’ indicating a disease state as bad as death. The difference in mean utility score between respondents with and without rheumatic disorders was valued using a threshold value for a quality-adjusted life year (QALY) of €20,000. For the Netherlands, we assume that the Dutch population is prepared to pay (at least) €20,000 for a QALY, that is, an additional year in perfect health .
To estimate the intangible costs, a new sample of respondents was recruited by using an existing panel of a market research agency complemented with people who responded to announcements on the websites of patient alliances for people with rheumatism and osteoarthritis. Respondents were classified into having rheumatic disorders or not using the same criteria as in the NMMS-2010, that is, having serious complaints (pain, aching, stiffness and/or swelling) in the past 12 months by persons that ever had been told to have arthritis by a doctor.
Material and methods
To assess the costs of rheumatic disorders in the Netherlands from the societal perspective we estimated the direct costs, indirect costs and intangible costs. Direct costs are all health-care costs that are directly related to the treatment of the disease, as, for example, hospital days, consultations with doctors and medication. Indirect costs arise as a secondary result of the disease, such as production losses in paid and unpaid work. Intangible costs are the monetary value of the inconvenience and difficulties due to rheumatic disorders. The costs were expressed in 2011 euro and comprise a 1-year period.
To estimate the direct and indirect costs of rheumatic disorders, data from the National Monitor on Musculoskeletal System 2010 (NMMS-2010) were used . The target population of the NMMS-2010 is the Dutch adult non-institutionalised population. A questionnaire was sent to a random sample of 40 000 household addresses. The persons from these households aged 18 years and older that had their birthday the soonest were asked to complete the questionnaire. The net response percentage was 22.4% ( n = 8904). The questionnaire contained questions on demographic characteristics, societal participation, life style, health and health-care use. The questions concerning health included questions on rheumatic disorders based on the module ‘arthritis’ from the Behavioral Risk Factor Surveillance System (BRFSS), Centers for Disease Control and Prevention (CDC) ( www.cdc.gov ):
- 1.
In the past 12 months, have you had serious pain, aching, stiffness or swelling in or around a joint?
- 2.
Have you ever been told by a doctor that you have arthritis? If so, which form?
Rheumatic disorders were defined as serious complaints (pain, aching, stiffness and/or swelling) in the past 12 months by persons who ever had been told by a doctor to have arthritis. In the NMMS-2010, 18.0% of the respondents reported to ever have been told to have arthritis. Of these respondents, 76.1% indicated to have had serious complaints in or around one or more joints in the past 12 months, which is 13.7% of all respondents. Extrapolated to the Dutch population of 13 million aged ≥18 years , it is estimated that 1.8 million are suffering from rheumatic disorders. Based on the form of rheumatic disease reported, a further categorisation was made in inflammatory rheumatic diseases ( n = 421,000), soft-tissue rheumatic diseases ( n = 242,000) and osteoarthritis ( n = 1,100,000).
Direct costs
Direct costs included in the present study are costs of visits to health-care providers, day treatment, hospitalisation, home care, diagnostics, medicine, aids and devices and surgery.
From the NMMS-2010, data about number of visits to health-care providers in the previous 12 months, number of day treatments and hospitalisations and hours of home care during the previous quarter were retrieved for people without and with rheumatic disorders by disease category (inflammatory rheumatic diseases, soft-tissue rheumatic diseases and osteoarthritis), age and gender. Quarterly data were extrapolated to a 1-year period. The amount of care use was multiplied with standard prices for the Netherlands (see Appendix 1 ) to obtain yearly costs. We assumed that rheumatic complaint-related costs were those costs of health care that exceeded the average costs of health care estimated for the population without rheumatic complaints. Rheumatic disorder-related costs were therefore estimated by the difference in costs per person between people with and without rheumatic disorders for different age categories and gender. Total difference in cost was obtained by multiplying the difference in cost per age category and gender with the number of people with rheumatic complaints in this category.
Rheumatic disorder-related costs of nursing homes and rehabilitation centres, medication, diagnostics and surgery could not be estimated from the NMMS-2010, and were therefore derived from other sources.
Costs of nursing homes and rehabilitation centres were based on the Dutch Cost of Illness Study 2007 ( www.kostenvanziekten.nl ) , a top-down cost-of-illness study in which total health-care costs were divided into specific disease categories, including rheumatoid arthritis, soft-tissue rheumatic diseases and osteoarthritis. Further, costs of medication (both over-the-counter (OTC) and prescription medications) were based on this study.
Costs of diagnostics for inflammatory rheumatic disease were assessed on the basis of the cost-of-illness study in Dutch rheumatoid arthritis patients . Cost estimates of diagnostics for patients with soft-tissue rheumatic diseases and osteoarthritis were not available.
To estimate the costs of surgery, numbers of specific rheumatic surgical operations were obtained from the National Medical Registration 2009 (LMR; www.kiwaprismant.nl ) and multiplied by their standard prices .
Use of aids and devices was retrieved from the NMMS-2010 data. Costs of aids and devices were assessed by averaging the total yearly costs per user with an invoice during that year over the period 2005–2009 ( www.gipdatabank.nl ). For simple aids and devices for mobility, it was assumed that these will last for 7 years on average, and for orthoses, joint protheses and house adaptations this period is assumed to be 15 years on average ( www.gipdatabank.nl ).
Indirect costs
The indirect costs included in this study are the costs of production losses in paid and unpaid work. Number of sick days, occupational disability and hours of unpaid work for persons with and without rheumatic disorders were obtained from the NMMS-2010 data.
We used two methods to estimate the costs of production losses in paid work, the friction cost method and the human capital approach . The friction cost method takes the employer perspective and assumes that within a production process ultimately everybody is replaceable and production losses only occur during the period that is needed to fill up the vacancy. Therefore, only sick days, were taken into account, that occur within the friction period of 22 weeks . For work absence longer than 22 weeks, productivity loss for 22 weeks was counted. Occupational disability does not lead to friction costs, as in the Netherlands people are only declared disabled after at least a year of work absence. The human capital approach takes the employee perspective and values all lost working days due to work absence, occupational disability and lower labour participation (less people with paid jobs and lower number of working hours a week).
Production losses were valued using the gender-specific average hourly wage, taking into account an elasticity of 0.8 between reduced labour time and productivity . This indicates that when people work less they first skip the less valuable activities, so the productivity will decrease less than proportionally. The average hourly productivity loss was €33.32 for men and €26.60 for women . Sick days were assumed to account for 8 h of work lost.
Unpaid work was reported by respondents of the NMMS-2010 in number of hours per day they perform housework and number of hours per week they perform volunteer work. The difference in hours between respondents with and without rheumatic disorders was valued using a price of €12.82 per hour, based on replacement costs for housework .
Intangible costs
Next to direct costs and indirect costs, rheumatic disorders will also result in inconvenience and difficulties for the patient. A method to value this impact in monetary terms is the WTP method . In this method, respondents are asked to indicate what the maximum amount is they are prepared to pay for a (hypothetical) treatment that would cure rheumatic disorders. We performed a WTP study by asking people to indicate how much additional health insurance premium they are willing to pay monthly for including such a treatment in the standard health insurance package in the Netherlands. The current premium for the obligatory basic health-care package is about €100 per month. Nine WTP intervals were shown to the respondents (€0, €1–5, €6–10, €11–20, €21–40, €41–60, €61–80, €81–100 and >€100) and subsequently the exact monthly amount respondents are willing to pay additionally was asked in the chosen interval. Finally, respondents were asked how sure they are that they would really pay this amount (not sure, more or less sure, sure). Respondents who indicated ‘not sure’ were excluded from the analysis .
Next to the WTP method, we used an alternative method to estimate intangible costs. Respondents were asked to indicate their quality of life on the Short Form (12) Health Survey (SF-12) . These scores were translated into a utility score . between ‘0’ and ‘1’, with ‘1’ indicating perfect health and ‘0’ indicating a disease state as bad as death. The difference in mean utility score between respondents with and without rheumatic disorders was valued using a threshold value for a quality-adjusted life year (QALY) of €20,000. For the Netherlands, we assume that the Dutch population is prepared to pay (at least) €20,000 for a QALY, that is, an additional year in perfect health .
To estimate the intangible costs, a new sample of respondents was recruited by using an existing panel of a market research agency complemented with people who responded to announcements on the websites of patient alliances for people with rheumatism and osteoarthritis. Respondents were classified into having rheumatic disorders or not using the same criteria as in the NMMS-2010, that is, having serious complaints (pain, aching, stiffness and/or swelling) in the past 12 months by persons that ever had been told to have arthritis by a doctor.
Results
Direct costs
Total additional costs of primary care due to rheumatic disorders in the Netherlands are assessed to be €909 million per year. In Table 1 , these costs are broken down to caregiver and major disease category (inflammatory rheumatic diseases, soft-tissue rheumatic diseases and osteoarthritis). More than 60% of the costs of primary care can be attributed to care provided by physiotherapists and occupational therapists, followed by 25% of the costs as a result of home care.
Related posts:
Introduction to special issue of best practices in rheumatology: Health economics of musculoskeletal diseases
Access to self-management education, conservative treatment and surgery for arthritis according to socioeconomic status
An update on the measurement of productivity losses due to rheumatoid diseases
The cost-effectiveness of total joint arthroplasty: A systematic review of published literature
Compromised access to prescriptions and medical care because of cost among US adults with arthritis
Impact of socioeconomic gradients within and between countries on health of patients with rheumatoid arthritis (RA): Lessons from QUEST RA
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