Development of 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria, Phase III-A/B Report: Defining and...

Area of Science:

• Rheumatology
• Immunology
• Clinical Criteria Development

Background:

• Antiphospholipid Syndrome (APS) requires precise classification for research.
• Previous criteria may not fully capture the spectrum of APS manifestations.
• An international initiative aimed to develop updated classification criteria.

Purpose of the Study:

• To define and structure candidate criteria for the 2023 ACR/EULAR Antiphospholipid Syndrome (APS) Classification Criteria.
• To refine clinical and laboratory domains for improved APS identification.
• To prepare criteria for validation in real-world cohorts.

Main Methods:

• Comprehensive literature reviews and expert consensus were employed.
• Domain subcommittees defined candidate criteria within clinical and laboratory categories.
• Definitions were finalized and approved by a Steering Committee.

Main Results:

• Clinical domains included macrovascular and microvascular thrombosis, pregnancy morbidity, cardiac valve disease, and thrombocytopenia.
• Laboratory domains specified coagulation-based (lupus anticoagulant) and solid phase assays (anticardiolipin, anti-β2-Glycoprotein I antibodies).
• Definitions were structured and confirmed using a derivation cohort and multi-criteria decision analysis.

Conclusions:

• The study successfully defined and structured candidate criteria for the 2023 ACR/EULAR APS Classification Criteria.
• These refined criteria are poised for validation to enhance APS research.
• The developed criteria encompass a broad range of clinical and laboratory manifestations of APS.