OBJECTIVES

This study aims to evaluate the utility of the 2023 ACR/EULAR antiphospholipid syndrome (APS) classification criteria in identifying primary APS patients at high risk of complications.

METHODS

In this single-center study, primary APS patients were classified according to both the revised Sapporo criteria and the 2023 ACR/EULAR criteria. The risk of complications was assessed using the adjusted Global Antiphospholipid Syndrome Score (aGAPSS).

RESULTS

Forty-five patients (73% females, median age 49 years) were included. Thirty-six patients met the 2023 ACR/EULAR criteria, all of whom also fulfilled the revised Sapporo criteria. Additionally, four out of nine patients not meeting the 2023 ACR/EULAR criteria satisfied the revised Sapporo criteria. Agreement rate between the two classification criteria was 91%, with a Cohen's kappa index of 0.66. Patients meeting the 2023 ACR/EULAR criteria had significantly higher aGAPSS scores compared to those who did not (13, 8-13 vs. 3, 0-5; p = 0.005). Furthermore, 55% of patients meeting the 2023 ACR/EULAR criteria were categorized as high risk based on aGAPSS scores, while those not meeting the criteria were predominantly categorized as low risk (77%). Interestingly, patients not meeting the 2023 ACR/EULAR criteria but fulfilling the revised Sapporo criteria had significantly higher aGAPSS scores compared to those not meeting either set of criteria (7, 5-13 vs. 0, 0-1.5; p = 0.015).

CONCLUSION

The 2023 ACR/EULAR criteria effectively identify primary APS patients at increased risk of complications, as indicated by the aGAPSS score. Key Points • Identifying primary APS patients at high risk of complications remains a significant challenge. • The 2023 ACR/EULAR criteria show a correlation with the aGAPSS score, exhibiting the highest correlation with laboratory domains and minimal correlation with clinical domains. • The 2023 ACR/EULAR classification criteria are effective in identifying primary APS patients at high risk of complications.