Background and aims To investigate association between smoking and vascular damages in patients with systemic lupus erythematous (SLE).

Methods A total of 500 SLE patients were enrolled in KORean lupus Network (KORNET) registry from January 2014 to January 2016. Disease activity and organ damage were measured by Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score and Systemic Lupus International Collaborating Clinics (SLICC) damage index. Association analyses using multivariate logistic regression analysis of covariance models with smoking status (three groups: current smoker, ex-smoker, never smoker) as outcome variable were conducted. We were divided into two groups depending on SLICC items (vascular vs. nonvascular involved items) according to the presence or absence of vascular damage including cardiovascular and peripheral vascular systems. Laboratory data was obtained including autoantibodies (antiphospholipid antibodies, anti-double-stranded DNA, etc.), complements, C-reactive protein.

Results There are significant differences in vascular component score of SLICC score among current, ex-, and never smokers (0.17±0.38, 0.03±0.17, and 0.03±0.20, p=0.003). whereas overall SLICC scores were similar among three groups (p=0.284). Current smoker showed higher vascular component score of SLICC score than never smoker (p=0.014) and than ex-smokers (p=0.039). Patients who has history of smoking exposure (current and ex-smoker) showed significantly higher positivity of antiphospholipid antibody (OR 2.58, 95% CI 1.31–5.08, p=0.006).

Conclusions This study revealed that smoking was associated with vascular component scores in SLICC damage index. It suggests that that smoking status may implicate the development of vascular events in SLE.