Risk factors of progression from discoid lupus to severe systemic lupus erythematosus: a registry-based cohort study of 164 patients.

ABSTRACT

BACKGROUND: No study has assessed the risk factors of progression from discoid lupus erythematosus (DLE) to severe systemic lupus erythematosus (sSLE) (defined as requiring hospitalization and specific treatment). OBJECTIVE: To identify the risks factors of and generate a predicting score for progression to sSLE among patients with isolated DLE or associated with systemic lupus erythematosus with mild biological abnormalities. METHODS: In this registry-based cohort study, multivariable analysis was performed using risk factors identified from literature and pruned by backward selection to identify relevant variables. The number of points was weighted proportionally to the odds ratio (OR). RESULTS: We included 30 patients with DLE who developed sSLE and 134 patients who did not. In multivariable analysis, among 12 selected variables, an age of <25 years at the time of DLE diagnosis (OR, 2.8; 95% CI, 1.1-7.0; 1 point), phototype V to VI (OR, 2.7; 95% CI, 1.1-7.0; 1 point), and antinuclear antibody titers of ≥1320 (OR, 15; 95% CI, 3.3-67.3; 5 points) were selected to generate the score. Among the 54 patients with a score of 0 at baseline, none progressed to sSLE, whereas a score of ≥6 was associated with a risk of approximately 40%. LIMITATIONS: Retrospective design. CONCLUSION: In our cohort, an age of <25 years at the time of DLE diagnosis, phototype V to VI, and antinuclear antibody titers of ≥1320 were risk factors for developing sSLE.