Reactive Thrombocytosis and Risk of Subsequent Venous Thromboembolism: a Cohort Study.
J Thromb Haemost. 2012 Jul 11;
Authors: Ho KM, Yip CB, Duff O
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 ?500x10(9) per liter, 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 censor date for survival and radiologically confirmed venous thromboembolism was October 31, 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 greater than 400x10(9) per liter. 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. © 2012 International Society on Thrombosis and Haemostasis.
PMID: 22784217 [PubMed - as supplied by publisher]