Abstract 4: 2019 Classification Criteria for Systemic Lupus Erythematosus

2019 European League Against Rheumatism/American College of Rheumatology classification criteria for systemic lupus erythematosus. Aringer M, Costenbader K, Daikh D, et al. Arthritis Rheumatol. 2019;71(9):1400-1412.

SUMMARY

• Systemic lupus erythematosus is a complex autoimmune disease with variable clinical features.
• The diagnosis can be difficult to make, and tests used to diagnose lupus or other rheumatologic illnesses are often misused. False positives due to low specificity are common if the tests are ordered in a low-prevalence population.
• The European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) collaborated on this expert-based recommendation.
• Four phases were used to make the recommendations, and worldwide experts were polled by a Delphi method, overseen by 12 lupus experts from the two societies. Multiple evidence-based literature reviews were also utilized.
• Conclusions
• An antinuclear antibody (ANA) test with titer >1:80 on HEP-2 cells or equivalent is necessary for entry into the criteria.
• This threshold is 98% sensitive.
• For this criterion, ANA-negative patients cannot be considered to have lupus.
• Caution: ANA is probably only 50% to 60% specific for lupus.
• In ANA-positive patients, use “additive criteria.”
• Points are assigned for clinical domains: 
• Constitutional, hematological, neuropsychiatric, mucocutaneous, serosal, musculoskeletal, renal
• Points are assigned for immunologic tests:
• Lupus anticoagulant, complement proteins, anti-double stranded DNA (anti-dsDNA), anti-Smith
• As clinically indicated, treatment of ANA-negative patients with lupus should still be considered but this group recommends that those patients not be enrolled in lupus trials.
• These new criteria, called the EULAR/ACR 2019 criteria, are 96% sensitive and 93% specific in the derivation cohort.

PMID: 31385462

EDITOR’S COMMENTARY - Steve Brown, MD
For a challenging diagnosis like lupus, we need to rely on expert opinion to make the diagnosis. This expert opinion is likely to become the standard by which we diagnose lupus. Although these recommendations were largely based on expert opinion, data from a systematic literature review were also included.

BOTTOM LINE: Clinicians should use these 2019 criteria to diagnose lupus, starting with an ANA as a necessary component of the diagnosis.