The economic weight of osteoarthritis in Europe






Mickaël HILIGSMANN,a,b PhD
Jean-Yves REGINSTER,b MD, PhD
aDepartment of Health Services Research, School for Public Health and Primary Care (CAPHRI)
Maastricht University – THE NETHERLANDS
bDepartment of Public Health Epidemiology and Health Economics
University of Liège, BELGIUM

The economic weight of osteoarthritis in Europe


by M. Hiligsmann and J. Y. Reginster,
The Netherlands and Belgium



This article aims to describe the economic weight of osteoarthritis (OA) in Europe based on published data and to underline the principal cost headings and their respective weights for patients and governments. This review suggests that OA has a significant economic effect not only on health care budgets, but also on patients, their employers, and their caregivers. The average total annual cost of OA per patient in Europe ranges from €1330 to €10 452. When considering only direct medical costs, the annual cost of OA ranged from €534 to €1788. In active patients, the indirect costs were found to be much higher than the direct costs. European studies are, however, not directly comparable with each other because of differences in the approach taken, in patient characteristics, in health care systems, and in the calculation of productivity losses. Our review confirms the immense burden of OA in Europe, which is expected to rise substantially further in the future with demographic changes and increasing obesity. Developing effective and efficient treatment programs for OA is becoming increasingly important to reduce the clinical and economic consequences of this major public health problem worldwide.

Medicographia. 2013;35:197-202 (see French abstract on page 202)



Osteoarthritis (OA), the most common form of arthritis, is a serious disease affecting the joints.1,2 OA affects nearly 10% of the population worldwide.3 In the United Kingdom, the lifetime risk of developing symptomatic knee and hip OA is estimated to be 44.7% and 25.3%, respectively.4,5 OA causes pain, stiffness, and severe disability. In the United States, knee OA is one of the five leading causes of disability among noninstitutionalized people.6 Symptomatic hip and knee OA are also associated with excess mortality7 and account for many hospitalizations, primarily related to knee and hip replacement surgery.8 Since OA is a disease whose prevalence increases with age, its prevalence and burden are expected to increase substantially in the near future due to demographic changes. In addition, obesity, which is rising worldwide, is a strong risk factor for knee and hip replacement.9 An increased trend in the prevalence of symptomatic knee OA and in the number of OA-related hospitalizations has already been observed recently.10

The economic cost of OA is also particularly high, resulting from decreased quality of life, hospitalizations, and loss of productivity. Cost-of-illness studies have become increasingly important to identify how much society is spending on a particular disease and thus help decision makers establish research and treatment priorities. In the United States, the annual medical care expenditures for OA were estimated at $185.5 billion (in 2007 dollars), of which $149.4 billion were insurer expenditures and $36.1 billion were paid directly by the patients. In Europe, some data has been published over the last few years on the economic impact of OA on individuals, including those in the workplace. The goal of this article is to review these publications so as to clarify the economic weight of OA in Europe based on available published data. Specific attention will be devoted to describing the principal cost headings (visits to health professionals, drugs, loss of productivity, etc.) and their respective weights for patients and governments.

Cost-of-illness evaluation

Burden-of-disease evaluation of OA aims to describe the impact of OA on society, including its impact on health care systems, patients, their caregivers, and their employers. Measuring the burden of disease can be very helpful in guiding the setting of health research priorities.11

The burden of OA can be measured with epidemiological parameters (incidence, prevalence) or with the impact of the disease on mortality, morbidity, quality of life, or health care costs. Cost-of-illness studies evaluate the direct and indirect health care costs of a particular disease over a period of time. This can be done using two different approaches: a prevalence based approach and an incidence-based approach. While the incidence-based approach estimates the costs of new cases of the disease during the period of time considered, the prevalence-based approach includes the costs of all the patients affected by the disease. Prevalence-based studies are far more common and are more suitable for the estimation of the annual burden of a disease.12

The cost of a disease can be estimated using either a “top-down” or a “bottom-up” approach. The top-down approach examines the costs in an aggregated form (such as national indicators) while in the bottom-up approach, the overall cost is based on the costs for the individuals.11 Most cost of- illness studies of OA in Europe have used the bottom-up method to estimate the economic burden of OA (see below).

The cost of a disease can be categorized into direct and indirect costs. Direct costs are those directly related to the disease, including, for example, visits to health care professionals, medical examinations, drug therapy, hospital admissions, and nonmedical costs. Indirect costs include productivity losses attributable to the disease resulting from absence from work and reduced effectiveness at work. These costs may be related to the patients themselves or to their caregivers.




Cost of osteoarthritis in Europe

A literature review was conducted using PubMed to find articles assessing the burden of OA in European countries between January 2000 and July 2012. The bibliographies of the papers included were also analyzed to search for additional references. Published studies on the economic cost of OA were found in Belgium, France, Germany, Italy, the Netherlands, and Spain. All of these studies, with the exception of the French study, used a bottom-up approach.


Figure 1
Figure 1. Direct and indirect costs of osteoarthritis in Belgium.

Based on a sample of 1811 active subjects with a mean age of 51 years. Total
cost per year = €1330. Direct costs are represented in red and indirect costs
in blue.
Data from reference 13: Rabenda et al. J Rheumatol. 2006;33:1152-1158.
© 2006, The Journal of Rheumatology.



_ Belgium
In Belgium, the cost of OA was assessed in 2004 in a sample of 1811 active subjects employed by the Liège City Council (mean age, 51 years) who were followed prospectively for 6 months.13 The self-reported prevalence of OA was 34%. The burden of OA was measured comprehensively, taking into account the direct medical costs (consultations with health professionals and with alternative medicine professionals, the number and type of medical examinations, the number of hospital stays and emergency department consultations, and all drugs taken) and the indirect costs (the number of sick leave days, and the number of days off work taken by active subjects helping relatives or friends with OA).

The mean total direct and indirect costs were estimated at €44.50 and €66.30 per OA patient-month, respectively, which, when extrapolated to 1 year, came to €1330 per OA patient annually. The average distribution of costs is shown in Figure 1. Consultations with health professionals, medical examinations, drugs, and hospital stays accounted for €23.70, €8.70, €6.70, and €4.90 per OA patient-month, respectively. Of all these direct costs, €29.10 (65%) was covered by the Belgian health care system and €15.40 (35%) was paid out of pocket by the patients. The average number of sick-leave days was 0.8 per OA patient-month, yielding—from the payer’s perspective—a cost of €64.50 per OA patient-month. The Belgian health care system covered 25.9% of all sick-leave payments, with employers covering the remaining 74.1%. Informal care was estimated to cost employers €1.80 per active subject-month, based on a mean of 0.02 days off work per active subject-month. Multiple regression analyses showed that age was a significant predictor of direct medical costs and that poorer quality of life was a major determinant of direct and indirect costs.

_ Italy
In Italy, the direct and indirect costs of knee OA were assessed retrospectively in a sample of 254 patients (mean age, 65 years) over a period of 12 months in 2000-2001.14 The cost per patient per year was estimated at €2170, of which 43% were direct costs—including medical (hospitalization, diagnosis, and therapies) and nonmedical costs (transport, temporary caregivers, and auxiliary devices)—and 57% were indirect costs (productivity losses and informal care).

The distribution of costs is shown in Figure 2. Hospitalization represented the largest medical cost, absorbing 25% of the direct resources (mean annual cost, €233). The annual cost of therapy was €136, of which 42% was spent on drugs and 58% on physiotherapy. Nonmedical costs (which represent 37% of the total costs) were mainly driven by temporary caregivers. In contrast with the study of Rabenda et al in Belgium,13 which only included active patients, the indirect costs were found to be mainly due to informal care provided by primary caregivers, which accounted for around 60% of the total indirect costs. The remaining indirect costs were due to loss of productivity (31%) and to other caregivers (9%). Sensitivity analyses revealed higher costs for patients with comorbidities and for women. Age was also shown to be a predictor of costs.

_ Netherlands
In the Netherlands, the productivity and medical costs of working patients with knee OA were recently assessed by Hermans et al.15 Loss of productivity and health care consumption were assessed by questionnaires in a sample of 117 knee OA patients participating in a randomized clinical trial investigating cost-effectiveness (mean age, 52 years). Interestingly, this study included the measurement of reduced work productivity while present at work in addition to loss of productivity resulting from absence from work.

The average total monthly knee OA–related costs were estimated at €871 per patient. The productivity costs accounted for 83% (€722) and the medical costs accounted for 17% (€149) of these costs. As observed in Figure 3, the medical costs were primarily driven by visits to primary (€62) and secondary care (€33), and by imaging (€40). Reduced productivity while present at work accounted for the majority (62%) of the productivity costs. The inclusion of loss of productivity while being present at work, which represented around 50% of the total costs (€448 per patient-month), could explain the relatively high cost of OA found in this study. Logistic regression analyses reported that increased pain during activity and performing physically intensive work were significantly associated with loss of productivity.


Figure 2
Figure 2. Direct and indirect costs of osteoarthritis in Italy.

Based on a sample of 254 patients with a mean age of 65 years. Total cost per
year = €2170. Direct costs are represented in red and indirect costs in blue.
Data from reference 14: Leonardi et al. Clin Exp Rheumatol. 2004;22:699-706.
© 2004, Clinical and Experimental Rheumatology.



Figure 3
Figure 3. Direct and indirect costs of osteoarthritis in the Netherlands.

Based on a sample of 117 active patients with a mean age of 51 years. Total cost
per year = €10 452. Direct costs are represented in red and indirect costs in blue.
Data from reference 15: Hermans et al. Arthritis Care Res. 2012;64:853-861.
© 2012, American College of Rheumatology.



_ Spain
The direct and indirect costs of osteoarthritis in Spain were estimated by Loza et al in 2007.16 Based on a sample of 1071 patients aged over 50 years (mean age, 71 years) with symptomatic and radiologic knee and/or hip OA who were seen at primary care centers in all provinces of Spain, data related to OA health resources utilization, patient and caregiver expenses, and time lost in the previous 6 months were collected in two separate interviews. The costs were divided into direct costs, including medical costs (professional time [all consultations], image, laboratory, and other tests, medications, and hospital admissions); and nonmedical costs (help at work and home, and self-care adaptive aids, devices, and assistive household equipment purchased), and indirect costs including compensation payments for lost productivity and housekeeping help costs if the patient was a homemaker.16


Figure 4
Figure 4. Direct and indirect costs of osteoarthritis in Spain.

Based on a sample of 1071 patients with a mean age of 71 years. Total cost
per year = €1502. Direct costs are represented in red and indirect costs in blue.
Data from reference 16: Loza et al. Arthritis Rheum. 2009;61:158-165. © 2009,
American College of Rheumatology.



The average total annual cost of osteoarthritis was estimated at €1502 per patient (€2007). Direct costs accounted for 86% of the total cost, mostly due to home, work, and self-care help (29%), professional medical time (21%), and hospital admissions (13%) (Figure 4). Indirect costs represented only 14% of the total cost, with the largest component related to providing help for housewives at home. Assuming a prevalence of knee and hip OA of, respectively, 10% and 4% in Spain, the authors estimated the national cost of OA at €4.7 billion, which represents 0.5% of the gross national product (GNP) of Spain. Using regression models, the authors also found that higher costs were associated with comorbidity, poorer health status, and lower WOMAC score (Western Ontario and McMaster Universities Osteoarthritis index).

_ France
In France, the direct and indirect costs of osteoarthritis were estimated by Le Pen et al using the top-down approach with nationwide data from 2001 to 2003.17 The direct costs of osteoarthritis were estimated at 1.6 billion Euros (€2002), representing approximately 1.7% of the expenses of the French health insurance system. Hospitalization represented 50% of the direct expenses. The costs of medication and physicians were estimated at €574 million (34%) and €270 million (16%), respectively. A 156% increase in direct medical costs was reported compared with 1993, which was related to an increase in the number of OA patients (+54%). The authors mentioned that the cost per patient increased by only 2.5% per year.

_ Germany
In a recent article, Sabariego et al aimed to determine the direct medical costs in patients with osteoporosis, osteoarthritis, back pain, or fibromyalgia in Germany.18 The mean direct cost of OA was estimated at €1511 in a sample of 97 OA patients. Medication, outpatient physician visits, nonphysician services, and inpatient services accounted for €699, €357, €171, and €175, respectively.

_ Other European countries
For other European countries, no detailed estimations of the cost of OA have been published in any of the journals included in the database we searched. In the United Kingdom, however, the National Institute for Clinical Excellence (NICE) has reported that the burden of OA represents 1% of the GNP.19

Discussion

This review suggests that OA represents a significant economic burden to patients and society in Europe. The annual cost of OA per patient ranges from €1330 to €10 452, depending on the country and the approach taken (Table).When considering only the direct medical costs, the annual cost of OA ranges from €534 to €1788. Drug therapies represent between 5.3% and 24.8% of the total direct medical costs,13-16 while hospitalizations and visits to health care professionals range from 15.2% to 39.6%,13,14,16 and from 35.5% to 53.9%,13-16 respectively. Indirect costs range from €205 to €8664 per year, depending on patient characteristics and the mode of calculation of productivity losses.13-16 The direct and indirect costs of OA were shown to increase with patient age and with poorer quality of life in several studies.13,14,16

Our review highlights the importance of indirect costs on the burden of OA. In particular, in studies assessing the burden of OA in active patients, indirect costs were found to be greater than direct costs.13,15 Indirect costs are especially high in OA as patients have to take days off work or early retirement, and/ or are less efficient at work.11 The analysis performed in the Netherlands showed that the indirect costs related to reduced work efficiency were considerable, representing more than 50% of the total cost of OA. 15 To adequately estimate the burden of OA, it is therefore important to estimate not only the indirect costs due to time off from work but also to reduced work efficiency at work.


Table
Table. Annual total costs, direct medical costs, and indirect costs
of osteoarthritis per patient in Europe. NR, not reported.



Cost variations were observed across the European studies. These studies are, however, not directly comparable because of differences in the approach taken, in patient characteristics, and in health care systems. Moreover, there are methodological differences in the calculation of productivity losses and no time adjustment was made for the costs. Despite such potential differences, the direct medical costs were very similar in Belgium, Italy, and Spain.13,15,16

The burden of OA is considerable, both from a societal and individual patient perspective. OA has a substantial effect not only on health care budgets but also on patients, their employers, and their caregivers. For example, in Belgium, the costs of OA in active patients are distributed among the employers (45%), the health care system (41%), and the patients themselves (14%). Therefore, in addition to pain and a poorer quality of life, patients living with OA may face significant personal expenses due to OA.

Our review confirms the great magnitude and economic impact of OA worldwide. Non-European countries have also reported a substantial burden of OA. For example, in the United States, the average direct cost of OA is approximately $2600 per year per person living with OA20, while in Canada, the excess burden of OA was recently estimated at Can$-1200.21

Cost-of-illness studies could be very useful in guiding health care priorities but there are limitations to their use for health care decision-making and they do not necessarily lead to more efficient health care systems. Cost-effectiveness analyses are potentially more interesting in order to assign health care resources more efficiently. By comparing the costs and effects of health interventions, health economic evaluation is a powerful tool for decision makers.22 However, current economic analyses in OA are limited and mainly pragmatic studies.23 Providing high-quality economic evaluations in OA would be of major importance to help decision makers make rational decisions and efficiently allocate health care resources dedicated to OA.

In summary, this review illustrates the immense burden of OA to patients and society in Europe. Developing adequate treatment programs for OA is becoming increasingly important to reduce the clinical and economic consequences of this major public health problem worldwide. Establishing the most effective treatments and determining the best use of resources should also become a priority in this area. _


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Keywords: burden, cost-of-illness, direct cost, economic, indirect cost, osteoarthritis