1. Department of Internal Medicine II, Rheumatology, University Hospital Halle (Saale), Halle (Saale), Germany
2. Department of Pediatrics I, University Hospital Halle (Saale), Halle (Saale), Germany
3. Institute of Medical Epidemiology, Biometrics, and Informatics, Medical Faculty of the Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany