Comparison of Composite Measure Remission Targets in Psoriatic Arthritis

Abstract

ObjectiveTo identify (1) which composite measure is the most stringent target of remission; and (2) which disease component target proves the most difficult to achieve in the different states of minimal disease activity (MDA), Composite Psoriatic Disease Activity Index (CPDAI), Disease Activity Index for Psoriatic Arthritis (DAPSA), and clinical DAPSA (cDAPSA) in patients with psoriatic arthritis (PsA).MethodsThere were 258 patients with PsA recruited. Disease remission was evaluated comparing 4 different composite measures and using remission cutoffs as previously proposed (very low disease activity [VLDA], CPDAI ≤ 2, DAPSA ≤ 4, cDAPSA ≤ 4).ResultsPatients met VLDA criteria (MDA 7/7) in 9.0% of visits, DAPSA remission in 19.8%, cDAPSA remission in 23.4% and CPDAI remission in 30.2%. Of 258 patients, MDA criteria (≥ 5/7) were fulfilled in 46.5%. Of those in MDA, VLDA criteria were reached in 25.0%. Patients met the pain visual analog scale (VAS) target in 57.5% of visits when they were in MDA, 43.3% when in low disease activity (MDA 5–6/7), and 44.8% when in CPDAI remission. Multivariate regression analysis revealed that pain VAS was the least likely target to be achieved. Patients with inflammatory-type back pain had significantly higher pain scores; further, a significant relationship was seen between Bath Ankylosing Spondylitis Disease Activity Index and pain VAS.ConclusionBased on our analysis, VLDA proved the most stringent target of disease remission in PsA compared to CPDAI, DAPSA, and cDAPSA. The pain VAS target of ≤ 1.5 cm was the most difficult component to achieve. CPDAI ≤ 2 was found to be the least stringent remission target; however, measurements of axial involvement, which contributed to the elevated pain VAS score in patients not achieving VLDA, were included as a domain in CPDAI only.