THE YIELD OF REPEATED ASSESSMENTS IN CHRONIC BACK PAIN PATIENTS SUSPECTED OF EARLY AXIAL SPONDYLOARTHRITIS: TWO-YEAR DATA FROM THE SPONDYLOARTHRITIS CAUGHT EARLY (SPACE) COHORT
Authors: Mary Lucy marques et al.
In patients with chronic low back pain of less than 2 yrs duration referred by general practitioners for rheumatological evaluation a diagnosis of axSpA can be reliably made, however diagnostic uncertainty often remains. The value of repeated assessments for making a definite diagnosis is unclear. This study used data from the SPACE cohort, a European multicenter cohort of patients with early chronic low back pain with less than 2 years duration. All patients had a baseline assessment of axSpA. If at least 1 major or 2 minor SpA features were present, the patients were reassessed at 3 months, 1 and 2 years including clinical examination, laboratory tests and imaging. The endpoints were clinical diagnosis of axSpA (with indication of level of confidence) by the treating rheumatologist and fulfilment of the ASAS criteria. 552 patients were included. In 175 patients a definite diagnosis of axSpA was made at baseline and in 165 patients at 2 yrs, around 90% were also classified as axSpA according to the ASAS criteria. In 32 patients the diagnosis changed to definite axSpA over 2 yrs. On average only 1 new SpA feature developed over 2 years. New MRI sacroiliitis was found in 8 patients of which 7 were HLA-B27 positive.
In patients with chronic back pain suspected of axSpA in which a clear diagnosis cannot be made, repeated assessments show only a modest yield in new diagnosis of definite axSpA over 2 years. In particular, repeating MRI shows a low diagnostic yield and should be considered primarily in HLA-B27 positive patients.