Establishment of the current classification criteria for axial spondylarthritis, rheumatoid arthritis and SLE in routine practice of German rheumatologists

Background. In Germany, the numbers of patients with spondylarthritides (SpA) and rheumatoid arthritis (RA) have increased. This rise was possibly promoted by the introduction of new classification criteria (CC) that enable an earlier recognition and the inclusion of less severe cases. The study explores how the new CC for axial SpA (axSpA) are incorporated into the clinical practice, compared with the CC for RA and systemic lupus erythematosus (SLE). In addition, the study investigated whether the new entity of non-radiographic axSpA (nr-axSpA) is accepted and used in Germany. Material and methods. In 2016, an online survey was performed among all rheumatologists registered in the German Society of Rheumatology (DGRh). In addition, 150 rheumatologistswere invited to the survey at the nationalmeeting of the DGRh in 2016. Results. Among 119 participating rheumatologists, 99% were familiar with the new CC for SpA and 82% applied them in practice (RA 99% and 80%, SLE 50% and 56%). 78% differentiated between radiographic and nraxSpA and 80% believed that a significant proportion of patients with nr-axSpA will never develop radiographic changes. 91% agreed that the new CC facilitated an earlier treatment start and 58% that the CC enabled more patients to receive biologicals. 50% shared the opinion that the criterion "chronic back pain" could lead to the classification of too many patients as having axSpA. It deemed possible to 65% that patients with nr-axSpA would be treated with biologicals in whom the diagnosis of axSpA could not be confirmed later on. 81% voted against the initiation of TNF inhibitors in nr-axSpA patients with normal CRP levels and normal MRI. 67% interpreted the MRI themselves and 30% stated that the MRI is evaluated according to validated standards by the radiologists. Among all axSpA criteria, HLA B27 and inflammatory back pain received the highest significance and the response to NSAID the lowest. Conclusion. The new CC and the entity of nraxSpA are accepted by German rheumatologists. A relevant proportion saw weaknesses of the new CC in the differentiation between nr-axSpA and non-specific chronic back pain. In practise, the interpretation of the CC with respect to the start of biologics is relatively strict, especially in cases with normal CRP and MRI. A ranking of axSpA criteria is commonly applied, although this was not initially intended in the CC.