Serum calcification propensity is independently associated with disease activity in systemic lupus erythematosus

PLoS One. 2018 Jan 24;13(1):e0188695. doi: 10.1371/journal.pone.0188695. eCollection 2018.


Background: Systemic lupus erythematosus (SLE) is associated with severe cardiovascular complications. The T50 score is a novel functional blood test quantifying calcification propensity in serum. High calcification propensity (or low T50) is a strong and independent determinant of all-cause mortality in various patient populations.

Methods: A total of 168 patients with ≥ 4 American College of Rheumatology (ACR) diagnostic criteria from the Swiss Systemic lupus erythematosus Cohort Study (SSCS) were included in this analysis. Serum calcification propensity was assessed using time-resolved nephelometry.

Results: The cohort mainly consisted of female (85%), middle-aged (43±14 years) Caucasians (77%). The major determinants of T50 levels included hemoglobin, serum creatinine and serum protein levels explaining 43% of the variation at baseline. Integrating disease activity (SELENA-SLEDAI) into this multivariate model revealed a significant association between disease activity and T50 levels. In a subgroup analysis considering only patients with active disease (SELENA-SLEDAI score ≥4) we found a negative association between T50 and SELENA-SLEDAI score at baseline (Spearman's rho -0.233, P = 0.02).

Conclusions: Disease activity and T50 are closely associated. Moreover, T50 levels identify a subgroup of SLE patients with ongoing systemic inflammation as mirrored by increased disease activity. T50 could be a promising biomarker reflecting SLE disease activity and might offer an earlier detection tool for high-risk patients.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Calcinosis / blood*
  • Cohort Studies
  • Female
  • Humans
  • Lupus Erythematosus, Systemic / blood*
  • Male
  • Middle Aged

Grant support

Calciscon AG provided support in the form of salaries for author AP, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The other authors received no specific funding for this work.