PO:04:061 | Higher prevalence of baseline comorbidities in patients developing difficult to treat psoriatic arthritis

Mario Ferraioli¹, Michelina Turri¹, Eneida Çela¹, Mauro Fatica¹, Paola Conigliaro¹, Elisabetta Greco¹, Alberto Bergamini¹, Maria Sole Chimenti¹. | ¹Rheumatology, Allergology and Clinical Immunology, Department of Systems Medicine, University of Rome, Tor Vergata, Rome, Italy.

Background. To evaluate baseline comorbidities as influencing factors for Difficult to Treat Psoriatic Arthritis (D2T-PsA) onset.

Methods. This is a retrospective case-control study, on PsA patients who had started their first bDMARD from September 2023 to May 2024 (T1). Those who had completed 1 year of continuous b/tsDMARDs therapy (T2) were enrolled. Demographic and clinical data were collected (Table 1) referred to T1, joint ultrasound (US) was performed at both evaluations. At T2, patients were divided in 2 groups: 1) D2T-PsA: according to Lubrano et al. with strictly inflammatory signs of active PsA (i.e. ultrasound-proven enthesitis/synovitis/tenosynovitis); 2) low disease activity (LDA): DAPSA<14, no ultrasound signs of active PsA. Descriptive statistics, Chi-square test, and Student’s t-test were used to compare baseline characteristics between groups. Logistic regression was used to estimate odds ratios for the association between baseline variables and D2T-PsA.

Results. Out of 224 patients enrolled, 168 (75.0%) and 54 (25%) were included in the LDA and D2T-PsA groups respectively. No significant differences were found in demographic characteristics between groups at T1. On the other hand, several baseline features and comorbidities appeared associated with 1 year incidence of D2T-PsA. Namely: smoking habit (p<0.001), presence of uveitis (p=0.01), dactylitis (p=0.03), axial disease (p<0.001), US proven bone erosions (p=0.03) and non-alcoholic fatty liver disease (NAFLD, p<0.001). Similarly, baseline number of swollen joints was associated to D2T-PsA development (p=0.04), while HAQ and VAS pain resulted higher in those achieving LDA at T2 (p=0.01 and 0.04, respectively). Furthermore, presence of different clinical features and comorbidities at T1 were associated with higher odds of developing D2T-PsA after 5 years (Table 2); including: smoking habit, HLA-B27, uveitis, enthesitis, axial disease, bone erosions at US and NAFLD. No significant relation was found for the other variables, including disease activity parameters.

Conclusions. Here, we have evaluated how basal clinical characteristics and comorbidities may influence the development of inflammatory-driven D2T-PsA. Reported data show how peculiar PsA features – pre-existing to bDMARD administration – are more prevalent in those that will develop D2T-PsA. Likewise, their presence also increases the odds of developing D2T-PsA. D2T-PsA represents a highly burdening condition, where inflammatory-driven forms are difficult to distinguish and manage correctly. In this context, as highlighted by recent publications from GRAPPA, pre-existing clinical conditions may reduce treatment response. Hence, understanding how they may influence D2T development is pivotal. While additional data are needed to understand how baseline features may influence therapy failure, from presented data it is possible to speculate that the baseline burden of PsA might be influential in its future development. References - Singla S et al. RMD Open 2024;10:e003809 - Chimenti MS et al. Biologics. 2020 Aug 20;14:53-75. - Lubrano E et al Rheumatol Ther 2023;10:1119–25