Evolution of disease burden over five years in a multicenter inception systemic lupus erythematosus cohort

Abstract

We describe disease activity, damage, and the accrual of key autoantibodies in an inception systemic lupus erythematosus (SLE) cohort. The Systemic Lupus International Collaborating Clinics (SLICC) International Research Network, comprising 27 centers from 11 countries, has followed an inception cohort of SLE patients yearly according to a standardized protocol. Of these patients, 298 were followed for a minimum of 5 years and constitute the study population. Disease activity was assessed using the SLE Disease Activity Index 2000 (SLEDAI-2K) and damage was assessed using the SLICC/American College of Rheumatology Damage Index (SDI). Antinuclear antibody (ANA), anti-DNA, and anticardiolipin antibody (aCL) levels and lupus anticoagulant were assessed yearly. Descriptive statistics were generated and repeated-measures general linear models were used to evaluate SLEDAI-2K and SDI over time between whites and nonwhites. Of the 298 patients, 87% were women, 55% were white, 12% were African American, 14% were Asian, 16% were Hispanic, and 2% were categorized as "other." At enrollment, the mean age was 35.3 years, the mean SLEDAI-2K score was 5.9, and the mean disease duration was 5.5 months. Mean SLEDAI-2K scores decreased in the first year and then remained low. SLEDAI-2K scores were significantly lower at each year in whites compared to nonwhites. Mean SDI scores increased progressively over 5 years; there was no significant difference between whites and nonwhites. As expected, ANA positivity was high and anti-DNA positivity was relatively low at enrollment, and both increased over 5 years. Although lupus anticoagulant increased slightly over 5 years, aCL positivity did not. Disease activity in newly diagnosed patients decreases over their first 5 years, while damage increases. Antibody positivity ran variable courses over this period.