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Thrombotic risk stratification by platelet count in patients with antiphospholipid antibodies: a longitudinal study
Author(s) -
Hisada R.,
Kato M.,
Sugawara E.,
Fujieda Y.,
Oku K.,
Bohgaki T.,
Amengual O.,
Yasuda S.,
Atsumi T.
Publication year - 2017
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/jth.13763
Subject(s) - medicine , platelet , antiphospholipid syndrome , hazard ratio , thrombosis , gastroenterology , confidence interval , immunology
Essentials Thrombotic risk stratification is an unmet need in antiphospholipid antibody carriers. Platelet count and antiphospholipid score ( aPL ‐S) were combined to predict thrombotic events. Patients with high aPL ‐S are at high thrombotic risk regardless of platelet count. If platelet count is low, patients with low aPL ‐S are also on high thrombotic risk.Summary Background Thrombocytopenia is a non‐criteria clinical manifestation of antiphospholipid syndrome. However, it remains to be elucidated whether thrombocytopenia increases thrombotic risk in antiphospholipid antibody (a PL ) carriers. Objectives To investigate the impact of platelet count in terms of predicting thrombotic events in a PL carriers, and to stratify the thrombotic risk by combining platelet count and antiphospholipid score (a PL ‐S), which represents a quantification of a PL varieties and titers. Patients/methods A single‐center, retrospective, longitudinal study comprising 953 consecutive patients who were suspected of having autoimmune disease between January 2002 and December 2006 was performed. Low platelet count was defined as a count of < 150 × 10 3 μL –1 at the time of a PL testing. Results A negative correlation was observed between a PL ‐S and platelet count ( r = − 0.2477). Among a PL ‐positive patients, those with a low platelet count developed thrombosis more frequently than those without (hazard ratio [HR] 2.95, 95% confidence interval [CI] 1.11–7.88). Among a PL ‐negative patients, no difference was found in the predictive value of thrombosis regardless of platelet count. Patients with a PL s were further divided into two subgroups according to a PL ‐S. Among low‐a PL ‐S patients, those with low platelet counts developed thrombosis more frequently than those without (HR 3.44, 95% CI 1.05–11.2). In contrast, high‐a PL ‐S patients developed thrombosis frequently regardless of platelet count. Conclusions a PL carriers with low platelet counts are at high risk of developing thrombosis. In particular, ‘low‐ aPL ‐S carriers’ may be stratified by platelet count in terms of predicting future thrombotic events.