Objectives The aim of this study was to determine the patterns of the accrual clinical symptoms, organ damage, and changes in disease activity in Korean patients with systemic lupus erythematosus (SLE).
Methods This large, well-defined, prospective cohort study included 996 patients with SLE who satisfied four American College of Rheumatology (ACR) criteria during 1998-2012. The accumulation of ACR criteria, the SLE Disease Activity Index 2000 (SLEDAI-2K), and the accrual SLE Disease Activity Index 2000 (SDI) score were assessed according to the disease duration (<5 y, ≥5 but <10 y, ≥10 but <15 y, and ≥15y). In a subgroup analysis of cases with a disease duration of 12±3m (n=120), the ACR criteria, SLEDAI-2K, and SDI score were assessed annually for 10y, and the changes in these parameters were analyzed using mixed linear models, adjusting for repeated measures.
Results The mean age at SLE diagnosis was 27.5±10.4 y, and 92.4% were women. At enrollment, the mean number of ACR criteria per individual was 5.6±4.3, the total SDI score was 0.4±0.9, and the mean SLEDAI-2K was 5.6±4.3. The common ACR criteria occurring during the follow-up period included: immunologic disorders (93%), hematologic disorders (93%), arthritis (66%), and nephritis (50%). The prevalence of these specific criteria was similar among the four disease duration groups, except for nephritis. The prevalence of nephritis increased from 38% in patients with early disease (<5 y) to 58% (>15 y). The accumulation of organ damage was most obvious in 431 patients (42.1%) whose mean SDI was 2.1±1.6. In half of these cases, organ damage developed within 5 y of SLE diagnosis. The most common organ system affected was musculoskeletal (14.9%) followed by renal (11.1%), the prevalence of which reached 22.5% and 17%, respectively, in the 15 y following SLE diagnosis.
Iincreased (5.0±1.2 to 5.7±1.3, p<0.0001). The prevalence of nephritis, serositis, and neuropsychiatric symptoms continuously increased over time. However, other symptoms were less common in the later periods of disease (>5 y). The total SDI score significantly increased (0.4±0.8 to 1.1±1.6, p<0.0001). Early in the course of disease, increase of musculoskeletal, neuropsychiatric, and renal symptoms were most prevalent. Increase of renal, optic, and cardiovascular damage predominated in the later course of disease. Optic symptoms, mainly cataracts, increased most dramatically over the 10 y follow-up period. The SLEDAIn the subgroup with a 10 y annual follow-up, the total number of ACR criteria significantly -2K score significantly decreased over time (p <0.0001). The proportion of SLEDAI-2K ≥12 did not decrease (p =0.3226), although this accounted for <5% of the subgroup.
Conclusions Overall, the total score of ACR criteria increased with time, mainly due to nephritis, serositis, and neuropsychiatric symptoms, but not all ACR criteria increased with time. The overall accumulation of organ damage is gradual, and patterns of damage were different as not all damage had the same pathogenesis or etiology. A small proportion of patients had very severe disease activity in spite of a decrease in the overall disease activity with time.
Disclosure of Interest None declared