Risk factors may predict progression of discoid to severe systemic lupus erythematosus

Diagnosis of discoid lupus erythematosus in patients aged younger than 25 years may predict the onset of severe systemic lupus erythematosus, according to study findings.

“No study assessed risk factors of progression from discoid lupus erythematosus (DLE) to severe systemic lupus erythematosus (SLE),” Lisa Fredeau, MD, of the department of dermatology and allergy, Tenon Hospital, AP-HP, Sorbonne University in Paris, and colleagues wrote.

In the registry-based cohort study, Fredeau and colleagues conducted a multivariable analysis to determine risk factors and generate a prediction score of who is likely to progress from isolated DLE to severe SLE, defined as requiring hospitalization and specific treatment.

Twelve variables as potential risk factors for severe SLE were included: age at DLE diagnosis; sex; phototypes V or VI; generalized DLE lesions; presence of arthralgia; baseline ANA titer of 1:320 or greater; presence of anti-dsDNA, anti-SSA and anti-Sm antibodies; presence of anemia or lymphopenia; and being classified as “mild” SLE at baseline. In addition, age at diagnosis was dichotomized with 25 years as the cutoff.

Thirty patients with DLE who developed severe SLE were compared with 134 patients with DLE who did not make this progression.

Age of younger than 25 years was associated with a 1-point score on the prediction model as a risk factor associated with severe SLE progression (OR = 2.8; 95% CI, 1.1-7). Phototype V-VI also had a score of 1 on the model (OR = 2.7; 95% CI, 1.1-7), while antinuclear antibody titers of 1:320 or greater (OR = 15; 95% CI, 3.3-67.3) had a score of 5 points. These factors were selected to generate the score, according to the findings.

For patients who had a score of 6 or more at baseline, the likelihood of progression to severe SLE was around 40%. Conversely, among 54 patients with a score of 0 at baseline, none progressed to this outcome.

The researchers noted the retrospective nature of the study as a limitation.

“In our cohort, age at DLE diagnosis [younger than] 25 years, phototype V-VI and ANA titers [of at least] 1:320 were risk factors of developing [severe] SLE,” the researchers wrote.

“DLE patients with a score [of at least] 6 may require a closer monitoring in particular urinalysis.”