Disease course patterns in systemic lupus erythematosus

BACKGROUND: Disease activity in systemic lupus erythematosus follows three different courses: long quiescent, relapsing remitting and persistently active. However, the patterns of disease course since diagnosis are not known. This study aimed to assess the prevalence and characteristics of such patterns over 10 years. PATIENTS AND METHODS: The inception cohort of the Toronto Lupus Clinic (≥10 year follow up, between visit interval ≤18 months) was investigated. Prolonged remission was defined as a clinical Systemic Lupus Erythematosus Disease Activity Index 2000 = 0 achieved within 5 years of enrolment and maintained for ≥10 years. The relapsing-remitting pattern was defined based on ≥2 remission periods (clinical Systemic Lupus Erythematosus Disease Activity Index 2000 = 0 for two consecutive visits). Patients with no remission were categorized as persistently active. Groups were compared for baseline characteristics, cumulative damage, flare rate, mortality and certain co-morbidities. RESULTS: Of 267 patients, 27 (10.1%) achieved prolonged remission, 180 (67.4%) relapsing-remitting and 25 (9.4%) persistently active. In total, 35 (13.1%) had only one remission period (hybrid). At enrollment, there were no differences regarding clinical and immunological variables. At 10 years, persistently active patients had accumulated significantly more damage than the prolonged remission and relapsing-remitting patients. Being of Black race and higher adjusted mean Systemic Lupus Erythematosus Disease Activity Index 2000 over the first 2 years were associated with a more severe disease course. Relapsing-remitting and persistently active patients had an increased flare rate and accrued more osteoporosis, osteonecrosis and cardiovascular events. CONCLUSIONS: Approximately 70% of systemic lupus erythematosus patients followed a relapsing-remitting course, whereas 10% displayed prolonged remission and another 10% a persistently active course. Early response to treatment was associated with a less severe course and better prognosis.