Background/Purpose: Rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (axSpA) are 3 common inflammatory rheumatic diseases that can lead to deformities and joint destruction; however, more research has been performed to characterize symptom presentation and the impact of disease burden on patients with RA compared with PsA and axSpA. Additionally, few studies have compared disease burden across patients with RA, PsA, and axSpA because there are limited disease measures that are directly comparable across all 3 diseases. The objective of this study was to compare the disease burden of patients diagnosed with RA, PsA, or axSpA enrolled in the US-based Corrona RA and PsA/SpA Registries.

Methods: This study included adult patients with RA enrolled in the Corrona RA Registry and those with PsA or axSpA enrolled in the Corrona PsA/SpA Registry between March 2013 and March 2018. Patient demographics, clinical characteristics, and disease activity measures collected at registry enrollment were compared between patients with RA vs PsA and patients with RA vs axSpA using t tests or Wilcoxon rank-sum tests for continuous variables and χ² or Fisher’s exact tests for categorical variables.

Results: A total of 11,350 patients with RA, 2003 with PsA, and 495 with axSpA were included. Patients with RA were older than those with PsA or axSpA (58.4 vs 53.6 and 47.6 years, respectively); a higher proportion of patients with RA were female (77% vs 52% and 36%) and a lower proportion were white (86% vs 94% and 93%) compared with patients with PsA or axSpA. Patients with PsA or axSpA had longer symptom duration (11.2 and 16.7 years) and disease duration (8.4 and 9.8 years) compared with those with RA (9.4 and 7.6 years, respectively) (Table). Patients with RA had a mean physician global assessment score comparable to that of patients with axSpA (27.3 vs 25.5) and higher than that of patients with PsA (18.6) (Table). Patients with axSpA had higher mean patient-reported pain, fatigue, and patient global assessment scores than those with RA (46.1 vs 39.5, 48.3 vs 43.4, and 50.2 vs 36.9, respectively), whereas patients with PsA had a comparable pain score (38.9 vs 39.5), lower fatigue score (41.1 vs 43.4), and higher patient global assessment score (43.2 vs 36.9) than those with RA (Table). Higher proportions of patients with PsA or axSpA reported experiencing ≥ 30 minutes of morning stiffness compared with those with RA (65% and 71% vs 62%) (Table).

Conclusion: The results of this real-world study indicate that, from a patient perspective, patients with PsA and axSpA have a disease burden comparable to or greater than patients with RA; however, the disease burden of PsA and axSpA may not be as well recognized in clinical practice compared with that of RA. These results provide important insights for physicians into the impacts of RA, PsA, and axSpA from a patient perspective and highlight the need to better understand disease burden in patients with PsA and axSpA.