OBJECTIVE: To assess the impact of clinical enthesitis by body site in patients with psoriatic arthritis (PsA).

METHODS: Adults with PsA enrolled in the Corrona Psoriatic Arthritis/Spondyloarthritis Registry (March 2013-March 2018) were included. Enthesitis at enrollment was assessed via the Spondyloarthritis Research Consortium of Canada Enthesitis Index and classified by affected sites (upper, lower, or both). Disease activity (eg, Clinical Disease Activity Index, clinical Disease Activity Index for PsA), patient-reported outcomes (PROs; eg, patient-reported pain and fatigue), and work productivity were compared between those with and without enthesitis using t or Wilcoxon rank-sum tests for continuous variables and χ2 or Fisher exact tests for categorical variables. The association of enthesitis with disease activity and PRO measures vs no enthesitis was modeled using multivariable-adjusted linear or logistic regression.

RESULTS: Of 2003 patients with PsA, 391 (19.5%) had enthesitis: 80 (20.5%) in upper sites only, 137 (35.0%) in lower sites only, and 174 (44.5%) in both. Regardless of location, disease activity and PROs were worse in patients with vs without enthesitis. In adjusted models, presence of enthesitis at any site was significantly associated with worse disease activity vs no enthesitis. Enthesitis in lower or both upper and lower sites was associated with higher pain and fatigue scores and greater work impairment vs no enthesitis.

CONCLUSION: Patients with clinical enthesitis had worse disease activity regardless of enthesitis location vs those without enthesitis, and patients with enthesitis in lower or both upper and lower sites had worse pain, fatigue, and work impairment.