Background/Purpose: In patients (pts) with psoriatic arthritis (PsA), early diagnosis and effective treatment has been shown to decrease functional disability and structural progression (Gladman DD, et al., Ann Rheum Dis, 2011; 70:2152-4). However, factors influencing treatment management decisions are poorly understood. The objective of this LOOP study was to evaluate the impact of clinical specialty setting and geographic regions on the management of pts with PsA in the United States (US).

Methods: LOOP was a multi-center, cross-sectional, observational study conducted across 44 sites in the US. Adult pts with a suspected or an established diagnosis of PsA who were routinely visiting a rheumatologist (rheum) or a dermatologist (derm) were eligible to participate in this study. Each enrolled pt was assessed by both rheum and derm. The association between enrolling or diagnosing clinical specialty setting or geographic regions (East, Central, and West) and time from symptom onset to PsA diagnosis and to different disease management steps were examined.

Results: Of 681 pts enrolled, 513 pts with a confirmed diagnosis of PsA were included in this analysis. Pt demographics and disease characteristics were comparable between PsA pts enrolled by rheum and derm settings. Current disease activity and disease burden were also mostly similar between rheum and derm settings (Table 1), although pts enrolled in derm setting had higher scores on skin measures and enthesitis. Interestingly, skin-related disease activity measures were similar among pts in East, Central, and West regions of the US, but there were significant differences in most other disease activity measures (Table 2). The median (95% CI) time from symptom onset to PsA diagnosis was 1.0 (0.5, 1.1) and 2.6 (1.7, 4.1) years (y) in pts enrolled in rheum and derm settings, respectively (P<.001). After PsA diagnosis, the median times to first csDMARD and to first bDMARD were 1.0 and 2.4 y, respectively. The median time from symptom onset to PsA diagnosis and from PsA diagnosis to first csDMARD and bDMARD did not differ significantly based on geographic regions.

Conclusion: The duration from symptom onset to PsA diagnosis was shorter in pts enrolled by rheums compared with derms. The median time was longer for treatment with first bDMARD compared with first csDMARD. There were differences in current disease activity and burden among pts based on enrolling specialty and geographic regions. Current disease activity and disease burden highlight the delay in PsA diagnosis and the need for appropriate management of PsA pts, irrespective of clinical specialty setting or geographic region.