Which factors predict progression from discoid lupus to severe SLE?

A diagnosis of discoid lupus erythematosus (DLE) at age 25 years or below, phototype V to VI, and antinuclear antibody titers of ≥1:320 are significantly associated with the development of severe systemic lupus erythematosus (SLE), according to a study.

A group of researchers performed a registry-based cohort study to identify the risk factors of and generate a prediction score for progression to severe SLE among patients with isolated DLE or associated with SLE with mild biological abnormalities.

Multivariable analysis was carried out using the risk factors identified from literature and condensed by backward selection to find relevant variables. The researchers proportionally weighted the number of points to the odds ratio (OR).

Thirty patients with DLE who developed severe SLE and 134 who did not were included in the study. Twelve variables were identified in multivariate analysis.

Of the variables, an age of <25 years at the time of DLE diagnosis (OR, 2.8, 95 percent confidence interval [CI], 1.1‒7.0; 1 point), phototype V to VI (OR, 2.7, 95 percent CI, 1.1‒7.0; 1 point), and antinuclear antibody titers of ≥1:320 (OR, 15, 95 percent CI, 3.3‒67.3; 5 points) were deemed fit to generate the prediction score.

None of the 54 patients with a score of 0 at baseline progressed to severe SLE. On the other hand, a score of ≥6 correlated with a risk of about 40 percent.

The study was limited by its retrospective design.