Validity of data collected in BIOREG, the Austrian register for biological treatment in rheumatology: current practice of bDMARD therapy in rheumatoid arthritis in Austria. - Rintelen, Bernhard; Zwerina, Jochen; Herold, Manfred; Singer, Franz; Hitzelhammer, Johann; Halder, Wolfgang; Eichbauer-Sturm, Gabriela; Puchner, Rudolf; Stetter, Miriam; Leeb, Burkhard F.; BIOREG investigator group (BMC Musculoskeletal Disorders, 2016)