Impact of disease activity on organ damage progression in systemic lupus erythematosus: University of Toronto Lupus Clinic Cohort.

OBJECTIVE: To examine the role of disease activity on organ damage over 5 years in patients with active systemic lupus erythematosus (SLE) despite standard of care. METHODS: This analysis of the University of Toronto Lupus Clinic cohort assessed organ damage (measured by Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index [SDI]) in patients with active SLE (SLE Disease Activity Index- 2000 [SLEDAI-2K] >/=6), using Cox proportional time-independent hazard models. Subgroup analyses were conducted in patients with SLEDAI-2K 6 or 7, 8 or 9, and >/=10 at baseline, and in the overall study population by steroid dose at study entry ( /=7.5 mg/day). RESULTS: Among the overall study population (N=649), SDI progression was observed in 209 (32.2%) patients over the 5-year follow-up. Mean SDI change in patients with a score >0 was generally consistent across all SLEDAI-2K subgroups. Multivariable analyses identified age at study start (hazard ratio [HR] 1.03, p<0.0001), steroid dose (HR 2.03, p<0.0001), immunosuppressants (HR 1.44, p=0.021), and SLEDAI-2K (subgroup analyses HR 1.64 horizontal line 2.03, p=0.0017 horizontal line <0.0001) as the greatest risk factors for SDI progression, while a study start date after the year 2000 had a protective effect on SDI progression compared with a start date prior to the year 2000 (HR 0.65, p=0.0004). CONCLUSION: Patients within the higher SLEDAI-2K subgroups at study entry, or receiving high doses of steroids, were more likely to have organ damage progression.