Utility of repeat anti-dsDNA testing in patients with SLE: SMART-SLE

Monitoring disease activity in patients with systemic lupus erythematosus (SLE) involves regular testing of anti-double stranded-DNA (dsDNA) antibodies, because of their possible correlation with or prediction of disease flare. However, the utility of conducting repeated tests in patients who consistently show positive results for anti-dsDNA remains uncertain.

Yeo et al. published an article in Rheumatology, analyzing the usefulness of serial anti-dsDNA monitoring in predicting the risk of flare in patients with SLE who are persistently anti-dsDNA positive.¹ Here, we summarize their key results.

Methods¹

• The study was conducted on the Asia Pacific Lupus Collaboration 2013–2021 dataset.
• Patients were categorized based on their anti-dsDNA results as:
  • Persistently negative, who never had anti-dsDNA values above the upper limit of the normal range
  • Fluctuating, who had varying anti-dsDNA results between negative and positive
  • Persistently positive, who always had anti-dsDNA results above upper limit of normal range
• Anti-dsDNA results were standardized by calculating an anti-dsDNA ratio to the upper limit of normal cut-off.
• Cox regression models were used to determine the association of anti-dsDNA as a continuous variable with the risk of flare using the following two approaches:
  • absolute value of anti-dsDNA ratio; and
  • change in anti-dsDNA ratio from the previous visit, noted as amplitude and direction.

Key findings¹

• Data from 3,484 patients with 37,582 visits were analyzed
  • 92.3% were females and median age at enrolment was 39 years
  • 29.5% had persistently positive anti-dsDNA, 34.3% had fluctuating anti-dsDNA, and 36% had persistently negative anti-dsDNA
• Anti-dsDNA ratio >3, as an absolute value, was significantly associated with an increased risk of flare at the subsequent visit in persistently positive and fluctuating anti-dsDNA patients with SLE (Figure 1).
• Increase and decrease in anti-dsDNA by more than 2-fold compared with the previous visit were also associated with increased risk of flare in the persistently positive and fluctuating cohort (Figure 1).