Differences in clinical features between axial psoriatic arthritis and axial spondyloarthritis: a systematic review and meta-analysis of observational studies

The study compared clinical features of axial psoriatic arthritis (ax-PsA) and axial spondyloarthritis (ax-SpA) using a systematic review and meta-analysis. The analysis included 15 studies with a total of 2,704 patients with ax-PsA and 9,248 patients with ax-SpA. Results showed no significant differences between these two conditions in disease activity scores, spinal function scores, or C-reactive protein levels. A significant difference was found in HLA-B27 marker positivity, which was markedly lower in ax-PsA compared to ax-SpA (risk ratio 0.37). Axial psoriatic arthritis demonstrated slightly better functional outcomes than ankylosing spondylitis. The authors concluded that the difference in HLA-B27 positivity supports distinguishing these conditions as separate disease entities with similar inflammatory mechanisms.