Thrombotic risk factors in primary antiphospholipid syndrome: a 5-year prospective study.
OBJECTIVE
Because thromboembolic events are frequently observed in primary antiphospholipid syndrome (PAPS), we assessed the risk factors for new thrombotic episodes.


METHODS
Fifty-six PAPS patients (mean age, 37+/-10 years) were prospectively studied for 5 years. The preliminary Sapporo classification criteria for antiphospholipid syndrome (APS; a medium-high anticardiolipin antibody [aCL] titer and/or a positive lupus anticoagulant [LA] test in the presence of vascular thrombosis and/or pregnancy morbidity) were used to confirm the diagnosis. Thrombotic episodes or pregnancy losses before a diagnosis of PAPS were considered events, and any new disease manifestation other than thrombocytopenia was considered a recurrent event. Only patients with objectively verified thrombotic events were included in the study.


RESULTS
Twenty-one new thrombotic events were observed in 15 subjects (26.8%), including 3 (5.4%) who died during the follow-up. The patients with IgG aCL levels of >40 IgG phospholipid unit (GPL-U) showed a higher incidence of new thrombotic events (43.3%) than those with levels of < or =40 GPL-U (7.7%). Univariate analysis identified a history of recurrent clinical events (P=0.004), a highly positive aCL titer (P=0.007), and the presence of cardiac abnormalities (P=0.036) as significant risk factors for new thrombotic events. A multivariate regression model confirmed that an IgG aCL titer of >40 GPL-U was an independent risk factor for thrombosis (odds ratio, 9.17; 95% confidence interval, 1.83 to 46.05).


CONCLUSIONS
A high IgG aCL titer is the strongest predictor of new thrombotic events in PAPS patients.
Turiel
Maurizio
M
Department of Cardiology, Istituto Ortopedico Galeazzi, University of Milan, Via Galeazzi 4, 20161 Milan, Italy. maurizio.turiel@unimi.it
Sarzi-Puttini
Piercarlo
P
Peretti
Rossana
R
Rossi
Edoardo
E
Atzeni
Fabiola
F
Parsons
Wendy
W
Doria
Andrea
A
D000022:Abortion, Spontaneous; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D016736:Antiphospholipid Syndrome / Q000175:diagnosis / Q000473:pathology*; D015331:Cohort Studies; D004452:Echocardiography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D016682:Lupus Coagulation Inhibitor / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011247:Pregnancy; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D013921:Thrombocytopenia / Q000378:metabolism; D013927:Thrombosis / Q000175:diagnosis / Q000473:pathology*; D013997:Time Factors
D000925:Anticoagulants; D007074:Immunoglobulin G; D016682:Lupus Coagulation Inhibitor