Background:A recently conducted randomized controlled trial (Joint Resources Sedentary Behavior Intervention study (JR-SB)) aimed to reduce sedentary behavior and increase light-intensity physical activity in patients with rheumatoid arthritis (RA). Patients were recruited from a rheumatology outpatient clinic and the intervention consisted of three motivational counselling sessions followed by text message reminders. The results showed highly significant between-group differences on behavioral, patient-reported and cardio-metabolic outcomes, both on a short- and long-term basis (1;2). Since a relatively large fraction (58%) of invited patients initially declined to participate in the trial, we decided to explore if and how the declining patients differed from the included patients. The findings may inform which patient characteristics to consider in implementing a lifestyle intervention in clinical practice.Objectives:To compare socio-demographic, clinical and lifestyle factors between included patients and patients declining to participate in the JR-SB study at the time where study inclusion commenced.Methods:We conducted a retrospective register-based cross-sectional study. All patients with RA, who had been invited to participate in the JR-SB study during 2013-2014 were identified in the DANBIO registry. Patients’ clinical and lifestyle data were also retrieved from DANBIO while data on socio-demography was extracted from Statistics Denmark. Differences between participants and decliners were determined by an independent t-test or chi-square test.Results:Of invited patients (n=801), a total of 467 (58%) declined participation in the JR-SB study during 2013-2014. See Table 1 for characteristics and comparison of participants and decliners.Table 1.Participants’ and decliners’ characteristics; (n (%) unless otherwise stated)Participants(n=150)Decliners(n=467)P-value(x2)Women121 (80.7)358 (76.7)0.30Age (years), mean (SD)58.5 (11.7)60.8 (12.9)0.045aLiving with partner96 (64)293 (62.7)0.78Working57 (38)157 (33.6)0.15RA duration (years), mean (SD)13.8 (11.1)13.7 (10.8)0.92aPain (VAS), mean (SD)34.4 (21.8)29.1 (24.5)0.046aFatigue (VAS), mean (SD)44.2 (26.0)39.5 (28.4)0.14aSmoking(n=61)27 (44.2)(n=220)130 (59.1)0.041Regular exercise (min 1-2 times/week)(n=29)23 (79.3)(n=89)50 (56.2)0.026VAS – Visual Analogue ScaleNumbers in bold indicate the total number of responders on smoking and exercise statusaDetermined by an independent t-testConclusion:Patients who declined to participate in a randomized controlled trial aiming at reducing sedentary behavior were often smokers, had less regular exercise habits and were older than those who accepted to participate. This indicates that the intervention did not appeal to all patients with RA. The findings should be considered in the implementation of lifestyle interventions in clinical rheumatology practice.References:[1]Thomsen T et al. Ann Rheum Dis 2017 Sep;76(9):1603-6.[2]Thomsen T, et al. Arthritis Care Res (Hoboken) 2019 Sep 10.Disclosure of Interests:Tanja Thomsen: None declared, Mette Aadahl: None declared, Merete L. Hetland Grant/research support from: BMS, MSD, AbbVie, Roche, Novartis, Biogen and Pfizer, Consultant of: Eli Lilly, Speakers bureau: Orion Pharma, Biogen, Pfizer, CellTrion, Merck and Samsung Bioepis, Bente Appel Esbensen: None declared