Effect of prednisone administration on coagulation variables in healthy Beagle dogs

Background: Long-term corticosteroid therapy has been associated with increased risk of thrombotic disease in dogs. Objective: The purpose of this prospective study was to use thrombelastography (TEG) and thrombin generation (TG) to detect development of a hypercoagulable state in healthy Beagle dogs receiving oral prednisone. We hypothesized that administration of corticosteroids would result in a hypercoagulable profile on TEG tracings and an increase in TG. Methods: Six healthy adult Beagles from the University of Montreal's research colony were used to conduct a prospective longitudinal study in which all dogs received 1 mg/kg of prednisone orally once daily for 2 weeks, followed by a 6-week washout period, and then 4 mg/kg of prednisone orally once daily for 2 weeks. TEG tracings on citrated whole blood and TG measurements on frozen-thawed platelet-poor plasma were obtained before prednisone administration (baseline), at the end of the washout period, and at the end of both corticosteroid trials. Results: Significant differences compared with baseline values were obtained for K, a, and MA, with tracings compatible with a hypercoagulable profile following both corticosteroid trials. There was a significant increase in endogenous thrombin potential only after low-dose (1 mg/kg) prednisone. Conclusion: Administration of prednisone to healthy Beagles resulted in hypercoagulability as indicated by TEG tracings, whereas the effect on TG was more variable. Further studies are needed to determine the underlying mechanisms of hypercoagulability and its clinical impact.