Background In addition to gender and ethnicity, modifiable variables like geography, socioeconomic status, health system structure, education, and physician expertise may influence outcomes in systemic lupus erythematosus (SLE).
Objectives To compare characteristics of and treatment options for subsets of Chinese and American patients with SLE to elucidate factors that contribute to disease activity and damage.
Methods Chart review of 77 Chinese (Qingdao) and 48 Midwestern American (Louisville, Kentucky) patients meeting American College of Rheumatology (ACR) criteria for a diagnosis of SLE followed up for four years were analyzed retrospectively. Organ damage was assessed using the Systemic Lupus International Collaborating Clinics (SLICC)/ACR Damage Index (SDI), and disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Statistics were parametric exploratory tests of significance and multiple regression analyses in this hypothesis-generating effort.
Results The interval between the time of onset and diagnosis was 44 months shorter in the Chinese arm (p=0.001), and Chinese patients followed up at six times greater frequency than American patients (p<0.001). Despite the lack of formal matching, the two cohorts featured similar disease activity according to the SLEDAI. Based on the SDI, rates of organ damage were higher in the American group. Chinese patients received more steroids, cyclophosphamide, hydroxychloroquine, intravenous immune globulin, and cyclosporine than the Louisville group, while the Louisville patients received more mycophenolate mofetil and azathioprine (p=0.001).
Conclusions The establishment of follow-up and treatment of SLE differs in specific, identifiable ways between these subsets of Chinese and midwestern American patients. Greater access to and increased frequency of follow-up appears associated with a lesser degree of organ damage, supporting the treat-to-target concept as applied to SLE. Complete, controlled trials in both settings are necessary, and further detailed comparison of larger cohorts may inform conclusions about the likelihood of generalizability of trial results from one setting to another.
Disclosure of Interest None declared