Antiphospholipid Syndrome (APS) is an autoimmune disease that is characterized by persistent antiphospholipid antibodies (aPL). This condition can lead to the development of blood clots, complications during pregnancy, and non-thrombotic manifestations like cardiac valve disease.
The classification of APS is crucial for identifying individuals who can participate in research studies and ensuring that similar disease states are included and compared in clinical trials. To address the evolving understanding of APS, the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) collaborated on the development of a new classification system based on modern disease knowledge.
The new APS classification system aims to provide a tool that allows for the weighting of individual criteria and different risk profiles, while maintaining high specificity. The development of the criteria involved four key phases: generation, item reduction, definition, further reduction, and weighting, threshold identification, and validation.
After revisions and reductions, the updated classification system stipulates an entry criterion of at least one positive aPL test within 3 years of identifying an aPL-associated clinical criterion. This is followed by a set of weighted criteria, with each criterion assigned a score ranging from 1 to 7 points. The criteria are divided into six clinical domains, including macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematology. Additionally, two laboratory domains encompass assays and antibody tests, aiming to increase the specificity of the criteria. A patient is classified as having APS if they score at least 3 points from each of the clinical and laboratory domains.
The new classification criteria were tested in potential APS cases, displaying promising sensitivity and specificity. Particularly, the specificity of the new classification system reached 99%, compared to 86% achieved with the previous 2006 criteria. The high specificity is of utmost importance in classification criteria, as it ensures standardized and stringent definitions for consistency in clinical trials, even if it comes at the expense of sensitivity.
EULAR anticipates that the new classification system will support high-quality, risk-stratified epidemiologic studies and clinical trials in APS. Ultimately, it is hoped that these criteria will lead to enhanced patient care and improved management recommendations for individuals with APS.
: Updated Classification Criteria for Antiphospholipid Syndrome: Enhanced Patient Care & Management Recommendations.
1. Source: Coherent Market Insights, Public sources, Desk research
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