Background Smoking is associated with increased disease activity in patients with systemic lupus erythematosus1 (SLE) and cutaneous lupus erythematosus (CLE) in cross-sectional analyses.2
Objectives We determined the associations between smoking status, cutaneous activity, and SLE disease activity among patients enrolled in a US-based SLE Cohort featuring a large African-American population.
Methods The Hopkins Lupus Cohort was queried for demographic/clinical information and laboratory parameters between current smokers and never smokers among SLE patients. SLE patients that developed rash vs. those that did not (according to the SLEDAI criteria for rash) were compared with smoking status and the following co-variables: age, ethnicity, sex, ESR, urine protein/creatinine ratio, anti-Ro, anti-La, anti-DNA, Low C3, and Low C4.
Results Current smokers vs. never smokers. Current smokers were significantly more likely than never smokers to have an active rash (49.58% vs. 36.31%, p<0.0001) and ESR >20 (63.25% vs. 52.75%, p<0.0006). Non-smokers were significantly more likely to have anti-Ro antibodies as compared to current smokers (32.62% vs. 26.44%) with no significant differences found in anti-La, urine protein/creatinine ratio, anti-dsDNA antibody, low C3 or low C4.
SLE Patients who developed new rash during the course of follow-up vs. patients without rash. SLE patients who developed a new rash were significantly more likely than SLE patients without a rash to have a younger age of SLE diagnosis (30.69 vs. 32.79, p<0.0015), higher SLEDAI continuous score (5.53 vs. 2.26, p<0.0001) and SLEDAI score ≥2 (100% vs. 57.04%, p<0.0001), Urine protein creatinine ratio >0.5 (17.14% vs. 10.67%, p 0.0256), anti-dsDNA ≥10 (36.12% vs. 23.78%, p<0.0001), low C3 <79 (28.1% vs. 20.08%, 0.0001) and low C4 <12 (20.49% vs. 12.86%).
Association between smoking and new rash. Smoking was significantly associated with new rash in SLE patients after adjusting for sex, ethnicity, and hydroxychloroquine use (p<0.0001). In addition, duration from SLE diagnosis to new rash were compared between current smokers and never smokers. Both non-parametric Kaplan-Meier curve and a parametric Weibull curve demonstrated current smokers developed rash significantly earlier than never smokers. Based on the Weibull distribution, the hazard of developing a rash is 40% higher among current smokers than never smokers, with the effect persisting after adjusting for sex and ethnicity.
Conclusions Current smokers with SLE are significantly more likely than non-smokers to have an active rash. In addition, the hazard of developing a rash is 40% higher among current smokers than never smokers. SLE patients who developed rash as compared to patients that did not develop a rash had significantly increased SLE disease activity and several laboratory abnormalities including increased urine protein creatinine ratio >0.5 (17.14% vs. 10.67%, p 0.0256), anti-dsDNA ≥10 (36.12% vs. 23.78%, p<0.0001), low C3 <79 (28.1% vs. 20.08%, 0.0001) and low C4.
Ghaussy NO, Sibbitt W, Jr., Bankhurst AD, Qualls CR. Cigarette smoking and disease activity in systemic lupus erythematosus. The Journal of Rheumatology. 2003;30(6):1215–1221.
Piette EW, Foering KP, Chang AY, et al. Impact of smoking in cutaneous lupus erythematosus. Archives of Dermatology. 2012;148(3):317–322.
Disclosure of Interest None declared