Medscape reports on the revamped ACR-EULAR Antiphospholipid Syndrome Classification Criteria and what it means for clinical research according to HSS rheumatologists Medha Barbhaiya, MD, MPH and Doruk Erkan, MD, MPH.

Updated criteria for classifying antiphospholipid syndrome (APS) will increase the specificity of identifying patients with the condition to aid clinical research, according to researchers. The revamped criteria, originally presented in draft form at the American College of Rheumatology (ACR) 2022 annual scientific meeting, were published this year in late August.

APS classification criteria were last updated in 2006 and did not incorporate the wider range of manifestations of APS, including heart valve and kidney disease. The ACR and the European Alliance of Associations for Rheumatology (EULAR) jointly commissioned the update.

The new criteria include six clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and two laboratory domains (antiphospholipid antibody [aPL] tests by solid-phase assay and coagulation assay). The criteria are weighted, with items in each of the eight domains receiving a score between 1 and 7. Patients who score at least three points from all clinical domains as well as three points from the laboratory domains are classified as having APS.

Dr. Erkan and Dr. Barbhaiya explained what this new criteria will mean for clinical research. 

“The major problem with APS research has been the inclusion of a heterogeneous group of aPL-positive patients — for instance, patients with both low- and high-risk aPL and/or thrombosis risk profiles, or patients with controversial pregnancy-related manifestations. This heterogeneity makes it difficult to compare and generalize the results of studies in patients with APS. More specific classification criteria will standardize the identification of a homogeneous group of patients with APS for inclusion in clinical studies and trials, thereby enhancing study interpretation and applicability," Dr. Erkan said. 

"In addition to novel manifestations included in the new criteria, macrovascular events such as venous or arterial thromboses, which were also included in the previous criteria, now require careful consideration of risk factors present at the time of thrombotic events. Weighting thrombotic events by the presence or absence of provoking risk factors may seem like a minor nuance of the new criteria but is critical to how thrombotic events in APS should be considered. Furthermore, quantification of thrombotic events in this way should help ensure that those patients with highly likely APS are truly the ones being included in clinical studies and trials related to potentially risky treatments, such as long-term anticoagulation," explained Dr. Barbhaiya.

Read the full article at medscape.com.