AB1267\u2005THE PREVALENCE OF RHUPUS SYNDROME IN A MONOCENTRIC TERTIARY REFERRAL COHORT

Abstract

Background: Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are two systemic chronic autoimmune diseases characterised by a wide spectrum of clinical and immune-pathological features. In clinical practice, the concept of Overlap Syndrome is defined when the two diseases coexist in the same patient. Rhupus syndrome is a rare clinical condition, characterized by overlap of SLE and RA. However, it is still subject to debate whether the syndrome should be considered a distinctive entity or an aggressive form of SLE. To date, the estimated prevalence of rhupus is unknown. Objectives: To evaluate the prevalence of patients with rhupus syndrome in our tertiary care center. Methods: We chart-reviewed all patients with a diagnosis of SLE[1] or RA[2], based on the current ACR classification criteria, who presented to our outpatient clinic rheumatology unit. Clinical and laboratory data were retrospectively collected from patient notes. Diagnosis were systematically analyzed by two independent reviewers (SGF and ER). Disagreements were resolved by consensus; if consensus could not be achieved, a third party (SS) would provide an assessment of eligibility. Results: One-hundred eighty-two patients with a diagnosis of SLE and 253 patients of RA, were identified. Out of 182 SLE and 253 RA cases analysed, only 2 patients fulfilled rhupus criteria. The estimated prevalence in our cohort was 0.46% (2/437). Patients’ fulfilling the diagnosis of rhupus is resumed in Table 1. ANA anti-dsDNA RF (U/ml) anti-APCAs (U/ml) Articular involvement SLE extra-articular manifestations Immunosuppressive treatment undergone Patient 1 1:320 Homogeneous pattern Positive (IFI) 219 63 Erosions of MTF and ulnar deviation of the wrists leukopenia, malar rash hydroxychloroquine, methotrexate, leflunomide, sulfasalazine, ciclosporin, azathioprine, abatacept, rituximab, tocilizumab Patient 2 1:160Granular pattern Positive (IFI) 55 47.95 Loss of ICs, CMCs and MCPs joint space and bilateral MCP joint erosions (2nd-4th) Myelitis, leukopenia, malar rash, oral ulcers hydroxychloroquine, methotrexate, azathioprine, mycophenolate, tocilizumab In Figure 1 are illustrated the clinical manifestations of SLE (Panel A; Malar rash) and RA (radiograph-documented erosive polyarthritis) of the two patients.Figure 1 Additionally, we identified 7 patients (1.61% of the total cohort) that only partially fulfilled both criteria for SLE and RA. In detail, 1 patient (0.23%) manifested with an overlap of clinical manifestations of SLE and RA, while 1 patient had an overlap of both laboratory criteria. Two patients (0.46%) presented with clinical criteria of RA and laboratory criteria for SLE and RA and 3 patients (0.69%) with clinical criteria of SLE and laboratory criteria for SLE and RA. Patient’s selection is resumed in Figure 2.Figure 1 Conclusion: The prevalence of rhupus observed in our study was relatively low (0.46%). However, we identified up to 1.6% of patients partially fulfilling a diagnosis of rhupus. Rhupus syndrome is a rare and aggressive clinical condition and further prospective studies and an harmonization of classification criteria are highly needed. References [1] Hochberg MC. Updating the ACR revised criteria for the classification of systemic lupus erythematosus. Arthritis Rheum. 1997 Sep;40(9):1725. [2] Aletaha D, et al. 2010 rheumatoid arthritis classification criteria: an ACR/EULAR collaborative initiative. Ann Rheum Dis. 2010 Sep 1;69(9):1580–8. Disclosure of Interests: None declared