1 Department of Internal Medicine and Rheumatology, Justus-Liebig-University, Giessen, and Kerckhoff-Klinik, Bad Nauheim, Germany.
2 Department of Internal Medicine and Rheumatology, Justus-Liebig-University, Giessen, and Kerckhoff-Klinik, Bad Nauheim, Germany. u.mueller-ladner@kerckhoff-klinik.de.