SMART-SLE: serology monitoring and repeat testing in systemic lupus erythematosus—an analysis of anti-double-stranded DNA monitoring
Ai Li Yeo, Rangi Kandane‐Rathnayake, Rachel Koelmeyer, Vera Golder, Worawit Louthrenoo, Yi‐Hsing Chen, Jiacai Cho, Aisha Lateef, Laniyati Hamijoyo, Shue‐Fen Luo, Yeong‐Jian Jan Wu, Sandra Navarra, Leonid Zamora, Zhanguo Li, Yuan An, Sargunan Sockalingam, Yasuhiro Katsumata, Masayoshi Harigai, Yanjie Hao, Zhuoli Zhang, BMDB Basnayake, Madelynn Chan, Jun Kikuchi, Tsutomu Takeuchi, Sang‐Cheol Bae, Shereen Oon, Sean O’Neill, Fiona Goldblatt, Kristine Ng, Annie Law, Nicola Tugnet, Sunil Kumar, Cherica Tee, Michael Tee, Naoaki Ohkubo, Yoshiya Tanaka, Chak Sing Lau, Mandana Nikpour, Alberta Hoi, Michelle Leech, Eric F. Morand
Abstract
OBJECTIVE: Disease activity monitoring in SLE includes serial measurement of anti-double 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. METHODS: Data were analysed from patients in a multinational longitudinal cohort with known anti-dsDNA results from 2013 to 2021. Patients were categorized 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. RESULTS: Data from 37 582 visits of 3484 patients were analysed. Of the patients 1029 (29.5%) had persistently positive anti-dsDNA and 1195 (34.3%) had fluctuating results. Anti-dsDNA expressed as a ratio to the normal cut-off was associated with the risk of subsequent flare, including in the persistently positive cohort (adjusted hazard ratio [HR] 1.56; 95% CI: 1.30, 1.87; P < 0.001) and fluctuating cohort (adjusted HR 1.46; 95% CI: 1.28, 1.66), both for a ratio >3. Both increases and decreases in anti-dsDNA more than 2-fold compared with the previous visit were associated with increased risk of flare in the fluctuating cohort (adjusted HR 1.33; 95% CI: 1.08, 1.65; P = 0.008) and the persistently positive cohort (adjusted HR 1.36; 95% CI: 1.08, 1.71; P = 0.009). CONCLUSION: Absolute value and change in anti-dsDNA titres predict flares, including in persistently anti-dsDNA positive patients. This indicates that repeat monitoring of dsDNA has value in routine testing.