New Classification System for SLE May Aid Earlier Diagnosis

Inês L, Silva C, Galindo M, et al., Classification of Systemic lupus erythematosus: Systemic Lupus International Collaborating Clinics versus American College of Rheumatology criteria. Arthritis Care & Research. 2015;Accepted MS. Online Jan 7-15. soi: 10.1002/acr.22539

The new Systemic Lupus International Collaborating Clinics 2012 classification criteria (SLICC'12) are far more sensitive at identifying lupus patients in real-life clinical practice than the American College of Rheumatology 1997 criteria (ACR'97) – especially within the first 5 years of disease onset, according to a large population study.

The study, conducted among more than 2,000 SLE patients in Spain and Portugal, finds that the SLICC’12 is significantly more sensitive than the older ACR criteria set (93.2% vs 85.6% overall) and identifies many patients that the ACR criteria miss. 

The longer the time from disease onset, the fewer the differences between the two classification sets. After 20 years,  differences were negligible. 

The SLICC’12 has a broader scope than the ACR’97, with 18 items in the criteria set compared with 11 for the ACR.

A major change:  The SLICC’12 ends the so-called “double counting” of photosensitive malar rash as two separate criteria (as allowed with the ACR’97). This was the most frequent cause for losing SLE classification in the SLICC’12. But it affected few patients.

On the other hand, the SLICC’12 uses an “acute cutaneous lupus” classification rather than the malar butterfly rash in the ACR’97, and “chronic cutaneous lupus” rather than discoid rash. For this reason, a slightly higher proportion of patients scored the SLICC’12 chronic cutaneous lupus criterion compared to the ACR’97 discoid rash criterion.

Immunological abnormalities, such as low complement, and hematological problems, like thrombocytopenia, are listed as separate criteria items in the SLICC12, rather than within broad classifications as in the ACR’97.

The increased scope of clinical and immunological manifestations included in SLICC’12 may allow doctors to qualify patients as having SLE earlier in the disease course, the authors point out.

The criteria should enable including more SLE patients in clinical trials, the authors conclude. Despite the predominance of European Caucasians in the study group, they add, its large size (n=2.055 from 17 center) makes it representative of lupus patients in real-life clinical settings -- for whom diagnostic criteria have been lacking, they add.