AB0208 REDUCED HAND FUNCTION INDICATES HIGHER DISEASE ACTIVITY IN PATIENTS WITH RHEUMATOID AND PSORIATIC ARTHRITIS
Authors: B. Coppers, S. Heinrich, S. Bayat, K. Tascilar, A. Kleyer, D. Simon, I. Minopoulou, G. Corte, F. Fagni, V. Schönau, D. Bohr, S. Leyendecker, G. Schett, A. M. Liphardt
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Measuring disease activity in patients with inflammatory arthritis remains challenging and is mainly based on physician-dependent assessments, subjective measures and just one blood biomarker of inflammation with no indication of the subclinical or functional state of the patients [1, 2]. Patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA) present with impaired hand function compared to healthy controls [3, 4]. While hand function is well studied in RA patients [5], data is sparse for PsA patients. <h3>Objectives:</h3> To employ the association between clinical disease activity scores and objectively measured hand function impairment in RA and PsA patients. <h3>Methods:</h3> Three conventional hand function tests were performed by PsA (CASPAR criteria) and RA (ACR/EULAR 2010 criteria) patients (Internal Medicine 3 outpatient clinics Erlangen, Germany) and healthy controls (HC) (study: Ethics #357_20B, DRKS00032490). The clinically assessed disease activity scores (Disease Activity in Psoriatic Arthritis Score (DAPSA) [1], Disease Activity Score 28 (DAS28) [2]) and the best trial for each of the hand function tests were used for this analysis: the highest out of three trials for an isometric grip strength test (Dynamometer, Saehan, Korea, Figure 1 A), the highest out of two trials for a dynamic grip strength test (Martin Vigorimeter, Germany, Figure 1 B) and the fastest out of two trials for the fine motor skill Moberg Picking-Up Test (MPUT) (Figure 1 C) for each hand. Mixed-effect linear regression models adjusted for age were used to employ the associations between the clinical disease activity scores and hand function tests of the patients. Analyses were stratified by sex. <h3>Results:</h3> We included 76 PsA patients (37 male, 52.0±4.3 years; DAPSA: 10.2±7.1), 73 RA patients (24 male, 53.9±14.1 years; DAS28: 2.6±0.9), and 77 HC (37 male, 46.0±18.5 years) in this study. For RA patients one-unit increase of the DAS28 was significantly associated with reduced dynamic grip strength for both sexes (Table 1, p&lt;0.05) but not with a reduced isometric grip strength. Performance time of the MPUT was on average 11% (male) and 7% (female) longer with one-unit increase in the DAS28 score, but was not statistically significant. In PsA patients, a one-unit increase in the DAPSA score was associated with worse hand function on all measurements, but these were significant only in male patients (all p&lt;0.05, Table 1). The MPUT showed worse performance of 2% in males and 1% in females for each one-point increase of the DAPSA score. <h3>Conclusion:</h3> Increased disease activity is associated with reduced hand function in PsA and RA patients. The dynamic grip strength test (vigorimeter) seems to be more sensitive than the isometric grip strength test (dynamometer) to detect functional changes in relation to disease activity. For male PsA patients, the fine motor MPUT may be particularly suitable to reflect changes in disease activity. Longitudinal properties of these measurements, such as sensitivity to change, need to be further explored. An overall low disease activity in PsA and RA patients is a limitation of our study. <h3>REFERENCES:</h3> [1] Schoels et al. <i>Ann Rheum Dis. 2010,</i><b>69</b>(8):1441-1447. [2] Prevoo et al. <i>Arthritis Rheum</i> 1995, <b>38</b>(1):44-48. [3] Liphardt et al. <i>ACR Open Rheumatol</i> 2020, <b>2</b>(12):734-740. [4] Köprülüoğlu et al. <i>Clin Biomech (Bristol, Avon</i>) 2022, <b>95</b>:105640. [5] Eberhardt et al. <i>Scand J Rheumatol</i> 2008, <b>37</b>(2):109-112. <h3>Acknowledgements:</h3> This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – SFB 1483 – Project-ID 442419336, EmpkinS. <h3>Disclosure of Interests:</h3> <b>None declared.</b>