SLICC.pdf
SLICC most commonly refers to the SLICC/ACR Damage Index (SDI)—a tool that measures permanent, cumulative organ damage in SLE.
Explanation
Unlike activity indices (e.g., SLEDAI), the SDI is not about “how inflamed the patient is today.” It captures irreversible change that has occurred since the diagnosis of SLE, from any cause: lupus itself, treatment toxicity (especially glucocorticoids), or comorbid disease.
Key features:
- Damage must be persistent, typically present for ≥6 months, to be counted (to avoid scoring transient findings).
- It is organized by organ systems (commonly including ocular, neuropsychiatric, renal, pulmonary, cardiovascular, peripheral vascular, gastrointestinal, musculoskeletal, skin, endocrine/metabolic, and malignancy domains).
- Each item is scored present/absent; points are summed into a total SDI score (higher = more accumulated damage).
What it’s used for:
- Prognosis: higher SDI correlates with worse long-term outcomes, including disability and mortality risk.
- Quality and safety lens: it helps quantify harm from uncontrolled disease and from therapy (e.g., cataracts, avascular necrosis, osteoporosis-related fractures).
- Research: distinguishes “damage accrual” from “activity,” which is critical in trials and cohort studies.
LICC/ACR Damage Index (SDI) is scored as a cumulative count of irreversible organ damage that has occurred since SLE onset/diagnosis, regardless of cause (lupus, treatment toxicity, or comorbidity).
Explanation
What gets scored
- The SDI contains ~41–42 items across 12 organ domains (e.g., ocular, neuro, renal, pulmonary, cardiovascular/peripheral vascular, GI, musculoskeletal, skin, endocrine/metabolic, malignancy).
- An item is scored only if it reflects nonreversible change and is typically present ≥6 months, with important exceptions (e.g., MI and stroke are recorded once they occur).
How points are assigned
- Most items are binary (present/absent) and score 1 point.
- Some items allow higher scoring:
- End-stage renal disease (ESRD) is scored as 3 points (when present ≥6 months).
- A small set of events can be scored twice if two qualifying events occur ≥6 months apart (e.g., stroke, myocardial infarction, avascular necrosis, bowel infarct, tissue loss, malignancy—rules vary by item).
- Cumulative rule: once an item is scored, it stays scored going forward even if it later improves or is surgically corrected (because it marks that damage occurred).
Result
Interpretation in practice
- SDI = 0: no documented irreversible damage.
- SDI ≥ 1: any accrued damage (often used as the key threshold in studies).
- Higher SDI and SDI increase by ≥1 over time (“damage accrual”) are consistently associated with worse long-term outcomes (disability, quality of life, and mortality risk), so the SDI functions as a prognostic “scar burden” metric, complementary to activity indices like SLEDAI.