Factors associated with damage accrual in patients with systemic lupus erythematosus: results from the Systemic Lupus International Collaborating Clinics (SLICC) Inception Cohort

Abstract

Background and aims: We studied damage accrual and factors determining development and progression of damage in an international cohort of systemic lupus erythematosus (SLE) patients.

Methods: The Systemic Lupus International Collaborating Clinics (SLICC) Inception Cohort recruited patients within 15 months of developing four or more 1997 American College of Rheumatology (ACR) criteria for SLE; the SLICC/ACR damage index (SDI) was measured annually. We assessed relative rates of transition using maximum likelihood estimation in a multistate model. The Kaplan-Meier method estimated the probabilities for time to first increase in SDI score and Cox regression analysis was used to assess mortality.

Results: We recruited 1722 patients; mean (SD) age 35.0 (13.4) years at cohort entry. Patients with damage at enrolment were more likely to have further worsening of SDI (SDI 0 vs ≥1; p<0.001). Age, USA African race/ethnicity, SLEDAI-2K score, steroid use and hypertension were associated with transition from no damage to damage, and increase(s) in pre-existing damage. Male gender (relative transition rates (95% CI) 1.48 (1.06 to 2.08)) and USA Caucasian race/ethnicity (1.63 (1.08 to 2.47)) were associated with SDI 0 to ≥1 transitions; Asian race/ethnicity patients had lower rates of new damage (0.60 (0.39 to 0.93)). Antimalarial use was associated with lower rates of increases in pre-existing damage (0.63 (0.44 to 0.89)). Damage was associated with future mortality (HR (95% CI) 1.46 (1.18 to 1.81) per SDI point).

Conclusions: Damage in SLE predicts future damage accrual and mortality. We identified several potentially modifiable risk factors for damage accrual; an integrated strategy to address these may improve long-term outcomes.

Keywords: Corticosteroids; Inflammation; Outcomes research; Systemic Lupus Erythematosus.

Figure 1

(A) and (B) Kaplan–Meier plots demonstrating the estimate of the proportions of patients who remain free of damage progression/SDI worsening for the patients within the SLICC cohort who had their SDI reported at their baseline visit (n=671) (A) and in this cohort stratified by whether or not they had an SDI score 0 (n=541) or SDI >0 (n=130) at baseline (B). SDI, Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology (ACR) Damage Index.

Figure 2

Spider plot of how each component score of the SF-36 varies according to the damage state. BP, bodily pain; GH, general health; MH, mental health; PF, physical functioning; RE, role emotional; RF, role physical; SF, social functioning; VT, vitality. State 0: SDI 0; State 1: SDI 1; State 2: SDI 2; State 3: SDI 3; State 4: SDI 4; State 5: SDI 5 or more. SF-36, Medical Outcomes Survey Short-Form 36.