Thromboembolic events among adult patients with primary immune thrombocytopenia in the United Kingdom General Practice Research Database

Abstract

BackgroundThe risk of thromboembolic events in adults with primary immune thrombocytopenia has been little investigated despite findings of increased susceptibility in other thrombocytopenic autoimmune conditions. The objective of this study was to evaluate the risk of thromboembolic events among adult patients with and without primary immune thrombocytopenia in the UK General Practice Research Database. Design and MethodsUsing the General Practice Research Database, 1,070 adults (≥18 years) with coded records for primary immune thrombocytopenia first referenced between January 1 st 1992 and November 30 th 2007, and having at least one year pre-diagnosis and three months post-diagnosis medical history were matched (1:4 ratio) with 4,280 primary immune thrombocytopenia disease free patients by age, gender, primary care practice, and pre-diagnosis observation time. The baseline prevalence and incidence rate of thromboembolic events were quantified, with comparative risk modelled by Cox's proportional hazards regression. ResultsOver a median 47.6 months of follow-up (range: 3.0-192.5 months), adjusted hazard ratios of 1.58 (95% CI, 1.01-2.48), 1.37 (95% CI, 0.94-2.00), and 1.41 (95% CI, 1.04-1.91) were found for venous, arterial, and combined (arterial and venous) thromboembolic events, respectively, when comparing the primary immune thrombocytopenia cohort with the primary immune thrombocytopenia disease free cohort. Further event categorization revealed an elevated incidence rate for each occurring venous thromboembolic subtype among the adult patients with primary immune thrombocytopenia. ConclusionsPatients with primary immune thrombocytopenia are at increased risk for venous thromboembolic events compared with patients without primary immune thrombocytopenia. Database. Haematologica 2010;95:1167-1175. doi:10.3324/haematol.2009 This is an open-access paper. Thromboembolic events among adult patients with primary immune thrombocytopenia in the United Kingdom General Practice Research Database

Safety and efficacy of eltrombopag for treatment of chronic immune thrombocytopenia: results of the long-term, open-label EXTEND study

“…[29][30][31][32][33] Studies with different therapies that increase platelets in these patients through various mechanisms have reported TEEs, including IVIg, 34 corticosteroids, 35 anti-CD40 ligand, 36 and other TPO-R agonists. 37 Approximately 3% of patients had experienced TEEs before entering the eltrombopag ITP trials.…”

Is ITP a thrombophilic disorder?

“…To partially overcome this limitation, only annualized risk should be considered. In the studies mentioned in Table I, including patients treated before the availability of TPO-ra, the annualized risk of VTE in ITP patients seems consistently variable between 0.41 and 0.67, despite the different study designs, compared with a correspondent range in control population variable from 0.20 to 0.42 in the three studies with matched controls [12,13,15]. Enger's study did not seem to sufficiently describe the design for selecting matched control population, so the figure of 0.09 3 100 patient-years should be taken with caution in the calculation of IRR [16].…”

“…In summary, all population-based studies using either patients without ITP registered in clinical practice [12] or matched subjects from general population [13,15,16] show evidence that the risk for VTE is higher (around two times) in chronic ITP compared with controls. A trend for higher risk also appears in some subgroups, but usually without reaching statistical significance.…”

“…accepted threshold of 100 3 10 9 /L) [12]. Cases were matched 1:4 with 4,280 non ITP patients by age, gender, primary care practice and pre-diagnosis observation time.…”

Coexisting Cardiac and Hematologic Disorders

“…Circulating platelets are often large and immature, increasing the risk of thrombotic events 30 . Although rare, coexisting ITP and CAD has been managed by either traditional coronary artery bypass or percutaneous intervention; however, both pose significant management dilemmas.…”