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Thrombotic risk in patients with immune thrombocytopenia and its association with antiphospholipid antibodies
Author(s) -
Kim KiJo,
Baek InWoon,
Yoon ChongHyeon,
Kim WanUk,
Cho ChulSoo
Publication year - 2013
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/bjh.12318
Subject(s) - medicine , lupus anticoagulant , hazard ratio , thrombosis , antiphospholipid syndrome , confidence interval , incidence (geometry) , gastroenterology , cumulative incidence , proportional hazards model , risk factor , cohort , physics , optics
Summary Patients with immune thrombocytopenia ( ITP ) paradoxically have an increased risk of thrombosis. The presence of antiphospholipid antibodies ( aPL ) has been observed in a substantial proportion of ITP patients, but its clinical significance remains to be established. This study retrospectively investigated the prevalence and clinical significance of aPL in ITP patients and assessed the risk factors for thrombosis. One hundred and sixty‐five subjects with ITP were included in the study and followed for a mean period of 63·4 months. Sixty‐nine (41·6%) patients were positive for aPL at diagnosis, and their clinical characteristics and course of ITP were not different from those of aPL ‐negative patients. Twenty‐one (12·7%) patients developed a thrombotic event during follow‐up and the cumulative incidence rate ratio of aPL ‐positive to aPL ‐negative patients for thromboembolism was 3·15 [95% confidence interval ( CI ) 1·21–8·17] after adjusting for confounding factors. Lupus anticoagulant and hypertension were identified by Cox regression analysis as independent risk factors for thrombosis [hazard ratio ( HR ) 4·1, 95% CI 1·4–11·9, P = 0·009 and HR 5·6, 95% CI 1·9–15·8, P = 0·001, respectively]. Our results showed that a substantial proportion of ITP patients were aPL ‐positive, and that lupus anticoagulant and hypertension were independent risk factors for thrombosis. Detection of aPL can provide useful information for identifying patients at high‐risk for developing thrombosis.