Systemic lupus erythematosus (SLE) carries a highly variable prognosis for individual patients. The natural history of SLE ranges from relatively benign disease to rapidly progressive and even fatal disease. SLE often waxes and wanes in affected individuals throughout life, and features of the disease vary greatly between individuals.
The disease course is milder and survival rate higher in persons with isolated skin and musculoskeletal involvement than in those with renal disease and CNS disease. A consortium report of 298 SLE patients followed for 5.5 years noted falls in SLE Disease Activity Index 2000 (SLEDAI-2K) scores after the first year of clinical follow-up and gradual increases in cumulative mean Systemic Lupus International Collaborating Clinics (SLICC) damage index scores.
It is important to distinguish between the disease activity and the damage index (irreversible organ dysfunction). Although the most effective instrument to measure SLE disease activity is still open to debate, there are several validated measures, including the Systemic Lupus Activity Measure (SLAM), SLEDAI, Lupus Activity Index (LAI), European Consensus Lupus Activity Measurement (ECLAM), and British Isles Lupus Activity Group (BILAG) Index.