Performance of the 2023 American College of Rheumatology/EULAR Classification Criteria for Antiphospholipid Syndrome in a Mexican Cohort

Objective The objective is to assess the performance of the 2023 American College of Rheumatology/EULAR classification criteria (2023 AECC) for antiphospholipid syndrome (APS) in a Mexican cohort. Methods We enrolled patients with primary APS (PAPS) and secondary APS (SAPS) and a control group of nonautoimmune thrombophilia. We evaluated the fulfillment of the 2023 AECC and the 2006 revised Sapporo classification criteria (2006 RSCC) and their performance against the clinical diagnosis as the gold standard. The baseline Global APS Score (GAPSS) and the Damage Index for APS (DIAPS) at last follow‐up were calculated. Results We included 85 patients with PAPS, 54 with SAPS, and 50 with thrombophilia. According to the 2023 AECC criteria, 69 patients (81.2%) with PAPS, 28 patients (51.9%) with SAPS, and none of the patients with thrombophilia met the criteria. When comparing true positive (TP) (n = 69) versus false negative (n = 16) cases within the PAPS group, TP cases exhibited a higher frequency of thrombotic manifestations and IgM anti‐cardiolipin and IgG anti–β2‐glycoprotein‐I positivity. For PAPS, there was a correlation between the 2023 AECC score and both GAPSS (rho = 0.621, P < 0.0001) and DIAPS scores (rho = 0.433, P < 0.0001). When comparing the 2023 AECC with the 2006 RSCC, a lower sensitivity (81.2% vs 88.2%) but a higher specificity (100.0% vs 92.0%) was observed for PAPS. Similar findings were observed in SAPS. Conclusion In both PAPS and SAPS, the 2023 AECC have higher specificity than the 2006 RSCC. The main feature of patients with PAPS according to the 2023 AECC was thrombosis. These criteria might identify patients at higher risk of thrombosis and damage accrual.