Objectives: The aim of this study is to identify prognostic factors of persistent disease activity and long quiescence in systemic lupus erythematosus (SLE).
Methods: Patients enrolled in the Hopkins Lupus Cohort from 1987 to 2012, who attended at least three visits per year during 3 consecutive years following baseline and had available information on disease activity were included. Patterns of SLE disease activity over the 3-year period were defined as: persistent long quiescent (pLQ), persistent relapsing-remitting (pRR), persistent chronic active (pCA) and mixed based on Modified SLE Disease Activity Index (M-SLEDAI). Possible predictors of pCA (vs pLQ, pRR and mixed) and pLQ (vs pCA, pRR and mixed) were identified by univariate and multivariate logistic regression analyses.
Results: 916 patients were included. In the multivariate analysis, use of hydroxychloroquine (OR: 0.45, 95% CI 0.22 to 0.92, p=0.03), African American ethnicity (OR: 2.36, 95% CI 1.15 to 4.85, p=0.02) and baseline SLEDAI (OR: 1.10, 95% CI 1.03 to 1.17, p=0.005) remained significant predictors of pCA. Higher education (>12 years; OR. 2.07, 95% CI 1.07 to 4.03, p=0.03) and lower baseline SLEDAI (OR: 0.67, 95% CI 0.56 to 0.82, p<0.001) were significant predictors of pLQ, while African American (OR: 0.38, 95% CI 0.17 to 0.83, p=0.02) and female patients (OR: 0.26, 95% CI 0.12 to 0.57, p<0.001) were less likely to achieve pLQ.
Conclusion: African American ethnicity and high disease activity at baseline predict chronic activity in SLE, regardless of treatment, years of education and income. Higher education, low disease activity at baseline and male sex predict long quiescence. The use of hydroxychloroquine is independently associated with a lower risk of chronically active disease.
Keywords: disease activity; disease activity patterns; hydroxychloroquine; systemic lupus erythematosus.