Predictors for clinical outcome in psoriatic arthritis - what have we learned from cohort studies?

Psoriatic Arthritis (PsA) is a heterogeneous disease that ranges from a mild form of oligoarthritis to destructive polyarthritis. The burden of disease can be severe and comparable to that of rheumatoid arthritis. Identifying predictors of worse outcome may improve the understanding of the underlying mechanisms of the disease and may guide therapeutic management at the individual level. Longitudinal cohort studies identified predictors of long-term outcomes such as joint damage, physical function and work disability in PsA. In general, male gender and lower burden of inflammation at presentation predict better outcome while a delay in diagnosis, disability and joint damage are associated with worse long term outcomes. Several HLA alleles also identify patients who are likely to sustain joint damage.