In a paper published in Arthritis & Rheumatology, investigators including HSS rheumatologists Doruk Erkan, MD, MPH (North American Co-principal investigator [PI]), and Medha Barbhaiya, MD, MPH, and Stephane Zuily, MD, MPH, PhD (European Co-PI), a vascular medicine specialist at the Université de Lorraine, have unveiled a new classification criteria for antiphospholipid syndrome (APS), a life-threatening autoimmune clotting disorder.

The international initiative is jointly supported by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR). 

The methodology involved four phases: 1) criteria generation by surveys and literature review; 2) criteria reduction by modified Delphi and nominal group technique exercises; 3) criteria definition with the guidance of real-world patient scenarios, weighting via consensus-based multicriteria decision analysis, and threshold identification; and 4) validation using independent adjudicators’ consensus as the gold standard.

The new classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1–7 points each) clustered into 6 clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and 2 laboratory domains (lupus anticoagulant functional coagulation assays and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti–β₂-glycoprotein I antibodies). Patients accumulating at least 3 points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria versus the 2006 revised Sapporo classification criteria had a specificity of 99% versus 86%, and a sensitivity of 84% versus 99%.

The new classification criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research.

Read the full article at acrjournals.onlinelibrary.wiley.com.