P48 Are new 2019 SLE EULAR/ACR classification criteria useful in patients with rhupus?

Background Concomitant presence of systemic lupus erythematous (SLE) and rheumatoid arthritis (RA) in the same patient is known as Rhupus. Poliautoimmunity is not an uncommon phenomenon reported, but only a small series of patients have been described so far with Rhupus. This study aimed to explore the utility of 2019 EULAR/ACR criteria in patients with Rhupus. Methods Cross-sectional study conducted in 11 Rheumatology Departments at Catalonia (Spain). We included prevalent cases classified as Rhupus (RA ACR/EULAR 2010 and SLE-ACR 1997). Data of patients with SLE were selected as control in a ratio 2:1, matched by sex. Results 120 patients were included, 40 Rhupus and 80 SLE alone as controls. 95% were female, with a mean age of 51 yrs and mean of 13 yrs. The 2019 SLE EULAR/ACR criteria were met in 92,5% of the Rhupus and in the 96,3% of the SLE cohort (p\u003e0,05). Numerically, criteria score was higher in those patients with ‘pure’ SLE than Rhupus (21.3 ± 7.0 vs 18.8 ± 6.5, p=NS). Excluding articular domain, there were no significant differences among those who meet new criteria (65% Rhupus vs. 77% SLE (p\u003e0.05)). Proteinuria was the only domain significantly more common in patients with SLE alone. No other differences were found in other clinical or serological characteristics. Conclusion More than 90% of patients classified as Rhupus criteria fulfilled new SLE criteria. This study shows that the new 2019 SLE EULAR/ACR criteria are not useful to differentiate SLE and Rhupus patients. Further investigations are needed to measure their utility in clinical practice for detecting overlap presentation of RA and SLE.