178. Is Patient Uncertainty Associated with Outcomes in Systemic Lupus Erythematosus?

Abstract

(group i), 12 participants with PsA and no history of dactylitis (group ii), and a control group of 12 participants (group iii) were recruited. Plantar pressure measurements were undertaken barefoot and in footwear. Peak plantar pressure and pressure time integral were analysed at the most common and second most common sites of dactylitis reported in the foot; 4th and 2nd toes, and 4th and 2nd metatarsophalangeal joints (MTP) of the left foot. Temporal and spatial parameters of gait were collected. Patient reported impairment and footwear (FISAP), and activity limitation and participant restriction (FISIF) were reported using the Foot Impact Scale for Rheumatoid Arthritis (FIS-RA). Results: PsA patients had a mean disease duration of 4.58 years in both groups, a mean FISIF score of 7.16 in group i and 6.83 in group ii compared with 0.41 in the control group, and a mean FISAP score of 8.75 in group i and 5.75 in group ii compared with 0.16 in the control group; ANOVA analysis and subsequent post-hoc testing using Games–Howell test yielded significance. In both domains of the FISRA there was a significant difference between both PsA groups compared with the control group; PsA group i P1⁄40.00 and PsA group ii P1⁄40.00 in the FISIF domain, PsA group i P1⁄40.03 and PsA group ii P1⁄40.05 in the FISAP domain. Mean plantar pressures measurements barefoot and in-shoe were not significant between groups. No significant differences were reported in spatial and temporal parameters of gait between groups. Conclusion: This is the first exploratory study to investigate the mechanical factors that may cause dactylitis in PsA. FIS-RA scores indicate PsA patients have significant limitations compared with controls, but a history of dactylitis does not worsen patient reported outcomes. Although no significant differences could be reported in plantar pressure data or gait variables, the study was underpowered. A subsequent power calculation indicates that 60 participants per group would be needed to power a larger study. Exploration of shear and friction in the forefoot may provide insight for a biomechanical trigger to dactylitis. Disclosure statement: The authors have declared no conflicts of interest.