The following is a summary of “Use of the Bath Ankylosing Spondylitis Disease Activity Index in Patients With Psoriatic Arthritis With and Without Axial Disease,” published in the December 2023 issue of Rheumatology by Reddy et al.

Researchers conducted a retrospective study to assess the responsiveness of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) in psoriatic arthritis (PsA) and its ability to discriminate between axial (ax) and peripheral disease activity in PsA.

They included individuals with PsA initiating therapy in a US-based longitudinal cohort study. axPsA, often accompanied by peripheral disease, was defined based on Assessment of Spondyloarthritis International Society axl spondyloarthritis classification criteria or ax disease imaging features. Baseline BASDAI, individual BASDAI items, patient global assessment, patient pain, and Routine Assessment of Patient Index Data 3, along with score changes post-therapy initiation, were descriptively reported. Standardized response means (SRMs) were calculated as the mean change divided by the SD of the change.

The results showed that among individuals with axPsA (n = 40), the mean (SD) baseline BASDAI score at therapy initiation was 5.0 (2.2), while for those with peripheral-only disease (n = 79), it was 4.8 (2.0), with no significant difference in patient-reported outcome scores observed between the groups. Similarly, the mean change for BASDAI was comparable between ax and peripheral disease groups (-0.75 vs -0.83). SRMs also exhibited similar patterns across ax and peripheral disease for BASDAI (-0.37 vs -0.44) and individual BASDAI items.

Investigators concluded that BASDAI exhibits reasonable responsiveness in PsA but lacks differentiation between axPsA and peripheral PsA. 

Source: jrheum.org/content/early/2024/01/09/jrheum.2023-0504