Elevated Circulating Thrombomodulin Levels in Systemic Lupus Erythematosus: A Systematic Review and Meta-Analysis

Objectives: Thrombomodulin (TM) is closely related to the pathogenesis of autoimmune diseases, in-cluding systemic lupus erythematosus (SLE). However, current evidence on circulating TM levels in SLE pa-tients is contradictory. We conducted this meta-analysis to more accurately assess circulating TM levels in pa-tients with SLE and lupus nephritis (LN) and to analyze related influencing factors. Methods: Systematic search of relevant documents was conducted in PubMed, Embase, and The Cochrane Li-brary databases (up to 28 February 2021). Studies on the comparison of circulating TM between SLE patients and controls were screened and evaluated for inclusion. Random-effects model analysis was applied to calcu-late the combined standardized mean difference (SMD) with a 95% confidence interval (CI). Heterogeneity was estimated by Q statistics and I-2. Results: A total of 353 articles were identified, 14 provided adequate information for this study finally. The re-sults illustrated that SLE patients had higher TM levels than healthy controls (SMD=0.38, 95% CI: 0.02 to 0.74, p=0.04). Circulating TM levels were increased in patients with active SLE compared to inactive SLE pa-tients (SMD=1.12, 95% CI: 0.03 to 2.20, p=0.04). In addition, circulating TM levels of SLE patients with LN were higher than those without LN (SMD=4.55, 95% CI: 1.97 to 7.12, p=0.001). Conclusion: The circulating TM levels in SLE patients are enhanced. In addition, circulating TM levels may be practical in reflecting the disease activity and nephritis involvement of SLE patients.