GAPSS: the Global Anti-Phospholipid Syndrome Score

Objective. To develop and validate a risk score [global APS score (GAPSS)] derived from the combination of independent risk for thrombosis and pregnancy loss (PL), taking into account the aPL profile, conventional cardiovascular risk factors and the autoimmune antibody profile.

Methods. This cross-sectional study included 211 consecutive SLE patients. Data on clinical manifestations, conventional cardiovascular risk factors, aPL profile, ANAs, ENA and anti-dsDNA were collected. Long-term low-dose aspirin, oral anticoagulant and HCQ treatment were also included in the analysis. Patients were randomly divided into two sets by a computer-generated randomized list. We developed GAPSS in the first set of patients (n = 106), assigning the risk factors identified by multivariate analysis weighted points proportional to the β-regression coefficient values. GAPSS was validated in the second set of patients (n = 105). The relationship between GAPPS and thrombosis and/or PL was analysed.

Results. In the first set, higher values of GAPSS were seen in patients who experienced thrombosis and/or PL compared with those without clinical events [GAPSS 9.3 (4.8) (range 1–19) and 5.3 (4) (range 0–16), P < 0.001]. Also taken separately, patients who experienced thrombosis or PL showed higher GAPSS compared with those without clinical events [GAPSS 9.6 (4.8) (range 1–19) vs 4.9 (5) (range 0–14), P = 0.027 for thrombosis; 7.3 (5) vs 3.9 (5.1) (range 0–16), P = 0.024 for PL, respectively]. In the second set, the results were similar, with statistically higher values of GAPSS in patients with a clinical history of thrombosis and/or PL compared with those without events [GAPSS 9.5 (5.6) (range 0–20) and 3.9 (4.1) (range 0–17), P < 0.001). Higher values were also seen when subclassifying the patients according to the clinical manifestation, thrombosis or PL [GAPSS 9.5 (5.6) (range 0–20) vs 4.8 (5.4) (range 0–17), P = 0.036 for thrombosis; 7.9 (3.3) vs 3.8 (5.4) (range 0–16), P = 0.037 for PL, respectively).

Conclusion. These data propose a substantial improvement in risk prediction of thrombosis or PL in SLE based on assessment of the GAPSS, a quantitative scoring system.