Multimodal Imaging of Structural Damage and Inflammation in Psoriatic Arthritis: A comparison of DMARD-Naive and DMARD-Failure Patients.

Objectives: To compare inflammatory and structural differences in active Psoriatic Arthritis (PsA) between disease-modifying antirheumatic drug (DMARD)-naive and DMARD-failure patients using diverse imaging approaches for future analyses. Additionally, to explore the influence of patient characteristics (clinical and demographic variables) on imaging findings.

Methods: Of the 80 patients included from the first cohort of the ongoing multicentre TOFA-PREDICT trial, 40 were DMARD-naive and 40 were DMARD-failure (csDMARD failure; 1 prior bDMARD excluding etanercept was allowed), all meeting classification criteria for PsA with a minimum disease duration of eight weeks. Baseline conventional radiographs of hands and feet, MRIs of both ankles, and whole-body 18F-FDG PET/CT were evaluated for inflammatory and structural imaging parameters, including Sharp-van der Heijde (SHS), Heel Enthesitis Magnetic Resonance Imaging Scoring System (HEMRIS) and Deauville synovitis scoring. Differences between groups and the influence of patient characteristics were examined with multiple linear regression.

Results: At baseline, patient characteristics were similar between groups. Imaging parameters showed limited inflammation and structural damage. Inflammatory imaging parameters were not significantly different (p> 0.200). Among structural parameters, only HEMRIS Achilles tendon structural damage was significantly different (p= 0.024, R2=0.071) and, SHS Joint Space Narrowing was not statistically significant (p= 0.050, R2=0.048) with higher values for both in DMARD-failures. After correction of patient characteristics, these differences in imaging disappeared (both p> 0.600).

Conclusion: At baseline, PsA patient groups were comparable concerning structural and inflammatory imaging parameters, especially after correcting for patient characteristics. Thus, DMARD-naive and DMARD-failure patient groups may be combined in future PsA progression and treatment decision studies.

Clinical Trial Registration Number: EudraCT: 2017-003900-28.