Ideal target for psoriatic arthritis? Comparison of remission and low disease activity states in a real-life cohort

Background Psoriatic arthritis (PsA) recommendations state that the target of treatment should be remission or Low disease activity (LDA). We used a real life dataset to compare different potential targets. Methods 250 PsA patients considered in an acceptable disease state according to their rheumatologist were included. Targets for remission were the DAPSA and cDAPSA remission (≤4), VLDA and PASDAS ≤ 1.9. LDA targets analyzed were the DAPSA ≤14, clinical cDAPSA ≤13, MDA, adjusted MDA targets: MDAjoints with both TJC and SJC mandated, MDAskin(PASI mandated), MDAjoints&skin; with TJC, SJC and PASI mandated. Results Comparison of the several candidate targets demonstrates that VLDA is achieved by the lowest proportion of patients and includes patients with the lowest residual disease activity compared with the other remission targets. The modified MDA measures are the most stringent targets for low disease activity in terms of residual disease on joints, psoriasis and enthesitis within patients achieving the target. In both remission and LDA, the inclusion of CRP did not show an added value. The exclusion of a skin domain, as in the DAPSA measures, resulted in negligence of skin disease and a negative impact on the QoL in some patients. Conclusions The different remission and LDA targets show us significant overlap between measures but these measures targeting the same definition do differ in terms of allowance of residual disease. Inclusion of laboratory markers seems unnecessary although exclusion of a skin domain may result in psoriasis not being assessed resulting in residual impactful skin disease.