Direct costs of ankylosing spondylitis and its determinants: an analysis among three European countries
- A Boonen1,
- D van der Heijde1,
- R Landewé1,
- F Guillemin2,
- M Rutten-van Mölken3,
- M Dougados4,
- H Mielants5,
- K de Vlam5,
- H van der Tempel6,
- S Boesen7,
- A Spoorenberg1,
- H Schouten8,
- Sj van der Linden1
- 1Department of Internal Medicine, Division of Rheumatology, University Hospital Maastricht, The Netherlands
- 2EA 3444, Department of Clinical Epidemiology and Evaluation, University Hospital Nancy, France
- 3Institute for Medical Technology Assessment, Erasmus University, Rotterdam, The Netherlands
- 4Department of Rheumatology, Université Réné Descartes, Hôpital Cochin, Paris, France
- 5Department of Rheumatology, University Hospital Gent, Belgium.
- 6Maasland Ziekenhuis Sittard, The Netherlands
- 7Faculty of Health Sciences, University Maastricht, The Netherlands
- 8Department of Methodology and Statistics, University of Maastricht, The Netherlands
- Correspondence to:
Dr A Boonen, Department of Internal Medicine, Division of Rheumatology, University Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands;
- Accepted 20 January 2003
Objective: To assess direct costs associated with ankylosing spondylitis (AS). To determine which variables, including country, predict costs.
Methods: 216 patients with AS from the Netherlands, France, and Belgium participated in a two year observational study and filled in bimonthly economic questionnaires. Disease related healthcare resource use was measured and direct costs were calculated from a societal perspective (true cost estimates) and from a financial perspective (country-specific tariffs). Predictors of costs were assessed using Cox’s regression analysis.
Results: 209 patients provided sufficient data for cost analysis. Mean annual societal direct costs for each patient were €2640, of which 82% were direct healthcare costs. In univariate analysis costs were higher in the Netherlands than in Belgium, but this difference disappeared after adjusting for baseline differences in patients’ characteristics among countries. Longer disease duration, lower education, worse physical function, and higher disease activity were predictors of costs. Mean annual direct costs from a financial perspective were €2122, €1402, and €941 per patient in the Netherlands, France, and Belgium, respectively. For each country, costs from a financial perspective were significantly lower than costs from a societal perspective.
Conclusion: Direct costs for AS are substantial in three European countries but not significantly different after adjusting for baseline characteristics among countries. Worse physical function and higher disease activity are important determinants of costs, suggesting better disease control might reduce the costs of AS. The difference in costs from a societal and financial perspective emphasises the importance of an economic analysis.
- ANOVA, analysis of variance
- AS, ankylosing spondylitis
- BASDAI, Bath Ankylosing Spondylitis Disease Activity Index
- BASFI, Bath Ankylosing Spondylitis Functional Index
- COI, cost of illness
- CT, computed tomography
- DMARD, disease modifying antirheumatic drug
- HR, hazard ratio
- IBD, inflammatory bowel disease
- NSAID, non-steroidal anti-inflammatory drug
- RA, rheumatoid arthritis