OP0229 ADJUSTED GLOBAL ANTIPHOSPHOLIPID SYNDROME SCORE (aGAPSS) AT DIAGNOSIS AND PERSISTENT ANTIPHOSPHOLIPID ANTIBODIES ARE STRONGER PREDICTORS OF RECURRENT THROMBOSIS IN PRIMARY ANTIPHOSPHOLIPID SYNDROME
Authors: P. Gaspar, A. R. Cruz-Machado, F. Ribeiro, V. R. Fonseca, S. Sciascia, L. Graca, V. C Romão
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> The adjusted Global Antiphospholipid Syndrome Score (aGAPSS) predicts thrombosis in antiphospholipid syndrome (APS). However, the influence of changes in aGAPSS over time on its ability to predict the risk of recurrent thrombosis has not been studied in primary APS (pAPS). <h3>Objectives:</h3> To assess the accuracy of the aGAPSS at diagnosis and follow-up in predicting thrombotic recurrence in thrombotic pAPS. <h3>Methods:</h3> Retrospective cohort study including 92 patients with thrombotic pAPS (Sidney criteria). We collected clinical and laboratory data at diagnosis and until the last available follow-up visit. We only considered recurrent events occurring during antithrombotic therapy. The aGAPSS were calculated at diagnosis and at the final visit by adding the weighted scores of hyperlipidaemia (3), hypertension (1); IgG/IgM anticardiolipin (ACL; 5), IgG/M anti-b2 glycoprotein I (ß2GPI; 4), and lupus anticoagulant (LA; 4). Using receiver operating characteristic (ROC) curves, we calculated the optimal cut-off of aGAPSS at diagnosis that predicted recurrence risk. Then, we applied the same cut-off value to aGAPSS at the last evaluation and explored the risk factors for recurrence using logistic regression. Areas under the curve (AUC) of the selected aGAPSS cut-off were determined. <h3>Results:</h3> Most patients were women (57.6%), with a mean (SD) age at disease onset of 42.7 (13.9) years, and a mean disease duration of 8.9 (7.0) years. Arterial thrombosis was the most common presenting thrombotic manifestation (51.3%), followed by venous thrombosis (44.6%). Acute cerebrovascular events (48.9) and venous thromboembolic disease (40.2%) were the most common manifestations. Recurrent thrombosis affected 23 (25.0%) patients after a mean follow-up time of 4.7 (4.8) years (27 events per 1000 patient-years). Comparing disease onset to the last follow-up, the proportion of patients with positive LA (67.4% vs. 32.6%, p&lt;0.001) and ACL (44.6% vs. 29.4%, p=0.033) decreased, unlike ß2GPI (39.1% vs. 30.4%, p=0.216) and triple positivity (17.4% vs. 18.5%, p=0.848), which remained stable. On the contrary, hypertension (28.3% vs. 42.4%, p=0.092) and hyperlipidaemia (25.0% vs. 45.7%, p=0.003) increased over time. In univariate analysis, disease duration (OR [95%CI], 1.08 [1.01-1.15], p=0.024), type of presenting thrombosis (arterial; OR 4.4 [1.5-13.2], p=0.008), ACL positivity at diagnosis (OR 3.10 [1.2-8.3], p=0.025), and persistent ACL (OR 3.0 [1.1-8.2], p=0.028), anti-ß2GPI (OR 3.6 [1.4-9.7], p=0.011), and triple positivity (OR 4.9 [1.6-14.9], p=0.005) at follow-up were associated with recurrent thrombosis. Persistent ACL (p=0.014), ß2GPI (p=0.013) and triple (p=0.009) aPL positivity remained significantly associated with recurrent thrombosis after adjusting for sex, age, disease duration and type of first event (arterial). The mean aGAPSS significantly decreased over time (<b>Figure 1A</b>) and was significantly higher in patients with recurrent thrombosis, both at diagnosis (<b>Figure 1B</b>) (OR 1.34 [1.2-1.6], p&lt;0.001) and at follow-up (<b>Figure 1C</b>) (OR 1.1 [1.0-1.2], p=0.008). The AUC showed that aGAPSS at diagnosis had a better diagnostic accuracy compared to aGAPSS at follow-up (<b>Figure 2A</b>). The ROC curve analysis showed that maximal AUC was obtained for aGAPSS at diagnosis ≥7 (<b>Figure 2A</b>), which was strongly associated with recurrence (OR 9.2 [2.5-33.9], p=0.001), even adjusting for sex, age, disease duration and type of first thrombotic event (arterial) (OR 15.4 [3.0-79.3], p=0.001). The same cut-off for aGAPSS at follow-up underperformed, with lower AUC (<b>Figure 2B</b>) and lacking an independent association with thrombotic recurrence on multivariate analysis (OR 2.78 [0.91-8.45], p=0.072) adjusted to the same variables. <h3>Conclusion:</h3> A value of aGAPSS ≥7 at diagnosis predicts recurrences in thrombotic pAPS with good accuracy. Given the expected rise in cardiovascular risk factors over time, the decrease of aGAPSS and its predictive power at follow-up is likely the result of seronegativization of individual aPL. aPL persistence may serve as a more reliable and easily accessible predictor of recurrent thrombosis, but need further investigation. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>