The most widely used composite disease activity score for systemic lupus erythematosus. Scores 24 clinical and laboratory features weighted by organ domain and severity. Used in clinical trials, treat-to-target monitoring, and biologic drug approval criteria for lupus.
SLEDAI-2K is a point-weighted composite disease activity score for SLE that evaluates 24 features across nine organ domains. Each feature carries a weight of 1, 2, 4, or 8 points depending on its clinical severity and relevance. The maximum possible score is 105, though scores above 20 are uncommon in clinical practice.
The "2K" version (updated in 2002 by Gladman et al.) differs from the original 1992 SLEDAI in that persistent features, such as lupus headache and visual disturbance, are scored as present even if they were present at the prior visit. This change more accurately reflects ongoing disease activity compared to the original version, which only scored new or recurrent features.
| SLEDAI-2K Score | Activity State | Clinical Meaning |
|---|---|---|
| 0 | Inactive | No active SLE manifestations. Low risk of organ damage accrual. Candidate for medication tapering in some cases. |
| 1 to 5 | Mild Activity | Low-level disease activity. Hydroxychloroquine optimization and close monitoring typically appropriate. |
| 6 to 10 | Moderate Activity | Active disease requiring treatment attention. Commonly meets threshold for biologic drug eligibility. |
| > 10 | High Activity | Significant disease burden. Prompt treatment escalation warranted. Scores above 12 associated with major organ involvement. |
A change of 4 or more points is generally considered the minimal clinically important difference (MCID) for SLEDAI-2K in clinical trials. The SRI-4 response (used in belimumab and anifrolumab trials) requires a 4-point or greater reduction in SLEDAI-2K.
The original SLEDAI was developed by Bombardier, Gladman, and colleagues at the University of Toronto and published in Arthritis and Rheumatism in 1992. It was derived from expert opinion and validated against physician global assessment and subsequent organ damage. The SLEDAI-2K revision was published by Gladman et al. in the Journal of Rheumatology in 2002, with the key modification allowing persistent features to continue scoring in subsequent visits.
Validation studies have demonstrated that SLEDAI-2K correlates with physician global activity, distinguishes active from inactive disease, and predicts subsequent organ damage accrual. The SRI-4 response criterion, defined as a 4-point or greater SLEDAI-2K reduction, was developed for the BLISS-52 and BLISS-76 belimumab trials and has become the standard efficacy endpoint in SLE trials.