Health care and burden of illness in systemic lupus erythematosus compared to rheumatoid arthritis: results from the National Database of the German Collaborative Arthritis Centres

Abstract

During the past 20 years, outcome studies in the rheumatic diseases have, on the one hand, given increasing evidence of the unfavourable long-term prognosis of rheumatoid arthritis (RA) and on the other hand determined continuous improvement of prognosis in systemic lupus erythematosus (SLE). The aim of the study was to investigate how this translates into the current spectrum of patients with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) seen by rheumatologists in Germany and to compare aspects of the burden of disease, disease outcomes and treatment between these two important rheumatic diseases using a large clinical database. Current health care was analysed with data from the German rheumatological database of 10 068 patients with RA and 1248 patients with SLE seen by rheumatologists in 2001. In addition, of a total of 3546 patients with SLE and 24 969 patients with RA seen at the German Collaborative Arthritis Centres between 1994 and 2001, 3465 cases of SLE were matched by age, sex, disease duration and referral status with a corresponding RA case. There were considerable differences in treatment of patients before referral to a rheumatologist and in rheumatologic care. In 2001, patients with SLE were treated by their rheumatologists mainly with antimalarials (AM, 37%), azathioprine (29%) and nonselective NSAIDs (16%). Of them, 61% received at least one immunosuppressive drug (including AM) plus glucocorticoids. In RA, methotrexate was the predominant medication (63%), and 56% received at least one immunosuppressive drug plus glucocorticoids. Matched pairs analysis showed that SLE patients with a short disease duration were almost equally burdened by pain, functional limitations and reduced health status as RA patients. After a disease duration of >10 years, however, patients with RA showed poorer outcomes than those with SLE: RA patients reported significantly more often severe pain (30% in RA versus 17% in SLE) and poor global health status (52 versus 38%), and their disease activity as well as severity was rated higher by the rheumatologists. In conclusion, comparing large groups of RA and SLE patients we found a similar burden in early but not in late disease. Taking into account limitations as to the generalizability of the results (recruitment in rheumatologic care, cross-sectional data, underestimation of SLE-specific outcomes), the discrepancy between the high increase in disease-related negative outcomes with longer disease duration in RA but not in SLE indicates a better long-term prognosis in SLE concerning the items observed. The great disparity in treatment intensity between rheumatologists and nonrheumatologists shows that the involvement of a specialist is needed equally in both diseases.