SMART-SLE: Serology Monitoring and Repeat Testing in Systemic Lupus Erythematosus.

Abstract

Background/Purpose: Disease monitoring in systemic lupus erythematosus (SLE) includes serial measurement of antidouble stranded-DNA (dsDNA) antibodies, but in patients who are persistently anti-dsDNA positive, the utility of repeated measurement is unclear. We investigated the usefulness of serial anti-dsDNA testing in predicting flare in SLE patients who are persistently anti-dsDNA positive. Method(s): Data were analysed from patients in a multinational longitudinal cohort who had at least two visits with antidsDNA results from 2013 to 2021. Patients were categorised based on their anti-dsDNA results as persistently negative, fluctuating or persistently positive. Cox regression models were used to examine longitudinal associations of anti-dsDNA results with flare. Result(s): Data from 37,582 visits of 3,484 patients were analysed. 1,029 (29.5%) of patients had persistently positive antidsDNA and 1,195 (34%) had fluctuating results. Anti-dsDNA levels were associated with increased risk of subsequent flare in the cohort overall, and this was also observed in persistently positive patients with an adjusted hazards ratio (95% confidence interval) of 1.56 (1.30, 1.87) (p< 0.001). Increase or decrease in anti-dsDNA more than two-fold compared to the previous visit was associated with increased risk of flare both in the whole cohort (p< 0.001) and in persistently positive patients (p=0.009). Conclusion(s): Absolute value and change in anti-dsDNA titers between visits predict flares, including in persistently antidsDNA positive patients.