Seventeen-year reassessment of diagnostic transitions, biologic therapy initiation and mortality in spondyloarthritis: results from the REGISPON-3 study.

objectivesTo evaluate disease evolution, diagnostic transitions, time to biologic treatment initiation and mortality in patients with spondyloarthritis (SpA) after 17 years from the original Spanish Registry of Spondyloarthritis (REGISPONSER).

methodsSpondyloarthritis Registry 3 (REGISPON-3) is a two-timepoint longitudinal study with patients fulfilling the European Spondyloarthropathy Study Group criteria participating in the REGISPONSER study and re-evaluated after 17 years. Clinical, laboratory, radiological and treatment data were collected and compared with baseline. Diagnostic changes according to the rheumatologist's judgement and their associated factors were analysed using multivariable logistic regression. Time to initiation of biologic therapy was evaluated using Kaplan-Meier survival analysis.

resultsA total of 536 patients from the REGISPONSER study conducted in 2004 were contacted in 2021 for the REGISPON-3 visit. Of these, 411 were physically re-evaluated, while 125 were confirmed deceased. Among the 411 patients, 31.6% experienced a change in diagnosis in the REGISPON-3 visit, mainly from undifferentiated SpA to axial SpA or psoriatic arthritis. In multivariable analysis, dactylitis, younger age and lower Bath Ankylosing Spondylitis Radiology Index scores were associated with diagnostic change. The use of biologic disease-modifying antirheumatic drugs (bDMARDs) increased from 13.1% to 52.1%. However, the median time to first bDMARD from symptom onset was 32 years (95% CI 30 to 35) and 28 years from diagnosis (95% CI 26 to 32). Among the 125 patients who died, the leading causes were infections (21.6%), cardiovascular (CV) events (20.0%) and cancer (19.2%).

conclusionsThis long-term reassessment reveals significant diagnostic changes in SpA and a mortality burden mainly attributed to infections and CV diseases.