Clinical Analysis of 56 Patients with Rhupus Syndrome: Manifestations and Comparisons with Systemic Lupus Erythematosus: A Retrospective Case–Control Study

To investigate the clinical features of Rhupus syndrome, we retrospectively reviewed the medical records of 56 patients with Rhupus who were hospitalized at the Peking Union Medical College Hospital, Beijing, China, between January 2000 and March 2013. We analyzed the clinical manifestations of Rhupus syndrome and compared these with a control group of 160 randomly selected systemic lupus erythematosus (SLE) patients without coexisting rheumatoid arthritis (RA). In our center, 1.30% (56/4301) of hospitalized SLE patients had Rhupus syndrome. The median disease duration was 8.0 years and 83.9% had RA onset. All Rhupus patients showed radiological erosion in the joints. Compared with the control group, Rhupus patients had a longer disease duration, higher prevalence of anticyclic citrullinated peptide antibody and rheumatoid factor, higher incidence of symmetrical polyarthritis with more joint deformities and rheumatic nodules, and increased erythrocyte sediment rate and c-reactive protein levels (P < 0.005). In addition, a lower SLE disease activity index and incidences of malar rash, hemolytic anemia, renal and neurological involvement (P < 0.005), and hypocomplementemia (P < 0.05) was observed in the Rhupus group. Rhupus syndrome is rare in SLE patients. Most Rhupus patients had RA onset and a distinctive clinical profile characterized by more severe RA-associated and mild SLE-associated damage. Specific autoantibodies and imaging findings could be helpful for making accurate Rhupus diagnoses.