Trajectories of severity pattern among patients with systemic lupus erythematosus: A retrospective cohort study

초록

Background: Survival rates for patient with systemic lupus erythematosus (SLE) have improved in recent with better disease monitoring, and treatment with immunosuppressants. Objectives: To examine algorithm for categorizing patients by SLE severity as mild, moderate, and severe based on SLE-related condition and/or usage of SLE medications in Korea. Additionally, we defined the trajectories of longitudinal course of severity patterns in patients who were newly diagnosed with SLE using group-based trajectory modeling (GBTM). Methods: We examined the algorithm for determining disease severity combining elements of disease activity with elements of cumulative damage and/or usage of SLE medications. We conducted a population-based retrospective cohort study using the nationwide healthcare claims information database of Korea from January 1, 2002, and December 31, 2018. Individuals with SLE were defined as patients who received at least one diagnostic for SLE (International Classification of Diseases, 10th revision code M32 with rare disease registration code V136). To define the trajectories of severity patterns, we performed GBTM during a 2-year follow-up in new SLE patients. In addition, chi-square tests and analysis of variance were used to compare characteristics between groups. Results: A total of 12 461 SLE were included in the analysis from 2006 to 2016. Five severity groups by GBTM were suggested by the optimal model, and patients were categorized as demonstrating consistently moderate, moderate-then-severe, moderate-then-mild, consistently mild, mild-then-moderate during follow-up. Patients with SEL severity worsened had a higher mean age then the other groups (Mean+SD; Total [37.5 ± 15.2], consistently moderate [35.6 ± 15.5], moderate-then-severe [41.8 ± 16.6], moderate-then-mild [37.7 ± 15.5], consistently mild [38.5 ± 14.5], mild-then-moderate [39.8 ± 15.3]). All characteristics included age, sex, geographic region, type of insurance, type of institution, income level, high, weight, and BMI at index date were significantly different groups (P < 0.05). Conclusions: We identified five trajectories of severity pattern in patients first diagnosed with SLE through GBTM. Further research with pattern of usage of SLE medications at first diagnosis is needed to clearly elucidate the factors that influence disease monitoring.