This work should be attributed to Department of Intensive Care Medicine, Royal Perth Hospital and School of Population Health of University of Western Australia.
Reactive thrombocytosis and risk of subsequent venous thromboembolism: a cohort study
Article first published online: 4 SEP 2012
© 2012 International Society on Thrombosis and Haemostasis
Journal of Thrombosis and Haemostasis
Volume 10, Issue 9, pages 1768–1774, September 2012
How to Cite
HO, K. M., YIP, C. B. and DUFF, O. (2012), Reactive thrombocytosis and risk of subsequent venous thromboembolism: a cohort study. Journal of Thrombosis and Haemostasis, 10: 1768–1774. doi: 10.1111/j.1538-7836.2012.04846.x
- Issue published online: 4 SEP 2012
- Article first published online: 4 SEP 2012
- Accepted manuscript online: 11 JUL 2012 11:14AM EST
- Received 26 April 2012, accepted 27 June 2012
- critically ill;
- deep vein thrombosis;
- pulmonary embolism;
- risk factors;
Summary. Background: It is uncertain whether reactive thrombocytosis is associated with an increased risk of venous thromboembolism. This study assessed the incidence of reactive thrombocytosis, defined as platelet count ≥ 500 × 109 L−1, at intensive care unit discharge and its association with subsequent venous thromboembolism.
Methods and Results: This cohort study involved linkage of routinely collected intensive care unit, laboratory, radiology and death registry data of critically ill patients admitted to the intensive care unit between January 2009 and March 2010. The census date for survival and radiologically confirmed venous thromboembolism was 31 October 2011. Of the 1446 patients who survived to intensive care unit discharge, 139 patients had reactive thrombocytosis (9.6%, 95% confidence interval [CI] 8.2–11.2%). Twenty-nine patients developed venous thromboembolism after discharge (2%, 95% CI 1.4–2.9%; 67 per 100 person-years, 95% CI 45–97) and the median time to develop venous thromboembolism was 25 days (interquartile range 8–148). Reactive thrombocytosis was associated with an increased risk of subsequent venous thromboembolism (hazard ratio 5.3, 95% CI 1.7–16.4), after adjusting for other covariates. Platelet counts explained about 34% of the variability in the risk of venous thromboembolism and had a relatively linear relationship with the risk of venous thromboembolism when the platelet counts were > 400 × 109 L−1. Venous thromboembolism after intensive care unit discharge was associated with an increased risk of mortality (hazard ratio 2.0, 95% CI 1.1–3.9), after adjusting for reactive thrombocytosis.
Conclusions: Reactive thrombocytosis during the recovery phase of critical illness was associated with an increased risk of subsequent venous thromboembolism.