To develop new classification criteria for systemic lupus erythematosus (SLE) jointly
supported by the European League Against Rheumatism (EULAR) and the American College
of Rheumatology (ACR).This international initiative had four phases. 1) Evaluation
of antinuclear antibody (ANA) as an entry criterion through systematic review and
meta-regression of the literature and criteria generation through an international
Delphi exercise, an early patient cohort, and a patient survey. 2) Criteria reduction
by Delphi and nominal group technique exercises. 3) Criteria definition and weighting
based on criterion performance and on results of a multi-criteria decision analysis.
4) Refinement of weights and threshold scores in a new derivation cohort of 1,001
subjects and validation compared with previous criteria in a new validation cohort
of 1,270 subjects.The 2019 EULAR/ACR classification criteria for SLE include positive
ANA at least once as obligatory entry criterion; followed by additive weighted criteria
grouped in 7 clinical (constitutional, hematologic, neuropsychiatric, mucocutaneous,
serosal, musculoskeletal, renal) and 3 immunologic (antiphospholipid antibodies, complement
proteins, SLE-specific antibodies) domains, and weighted from 2 to 10. Patients accumulating
≥10 points are classified. In the validation cohort, the new criteria had a sensitivity
of 96.1% and specificity of 93.4%, compared with 82.8% sensitivity and 93.4% specificity
of the ACR 1997 and 96.7% sensitivity and 83.7% specificity of the Systemic Lupus
International Collaborating Clinics 2012 criteria.These new classification criteria
were developed using rigorous methodology with multidisciplinary and international
input, and have excellent sensitivity and specificity. Use of ANA entry criterion,
hierarchically clustered, and weighted criteria reflects current thinking about SLE
and provides an improved foundation for SLE research.
