1. Institute for Outcomes Research, Centre for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
2. Ludwig Boltzmann Institute for Arthritis and Rehabilitation, Vienna, Austria
3. Karl Landsteiner Private University for Health Sciences, Krems, Lower Austria
4. Clinical Department of Rheumatology, Medical University of Vienna, Vienna, Austria
5. Department of Orthopaedics, Medical University of Vienna, Vienna, Austria