NEW YORK (Reuters Health) – When considering risk factors for venous thromboembolism, recent lengthy travel does not appear to be a significant candidate, according to results of a prospective, multicenter study published in the Annals of Emergency Medicine for August. On the other hand, the findings suggest that total body or single limb immobility or immobility due to neurologic disease double the risk.
“These data provide evidence that clinicians should consider immobility as a heterogeneous entity that should be parsed according to its root cause,” Dr. Jeffrey Kline, from the Carolinas Medical Center in Charlotte, North Carolina, and co-authors report.
Their study included 7940 emergency department patients who were evaluated for venous thromboembolism between 2003 and 2006. Clinicians documented the presence and causes of immobility in a Web-based electronic data collection form. There were 6 categories, as follows:
–Generalized: “Total body immobility, including bed-bound patients or patients who do not walk for periods exceeding 48 hours”
–Limb: “Cast or external fixator that immobilizes two or more contiguous joints.”
–Travel: “Generalized immobility lasting more than 8 continuous hours due to travel in the past 7 days”
–Neurologic: “Paralysis or paresis from brain, spinal cord, or neuromuscular disease or injury”
–Other: “Limited mobility from issues not listed above”
A total of 545 patients were diagnosed with venous thromboembolism within 45 days, and 1394 had at least one category of immobility.
Compared with patients with no immobility, limb immobility was most strongly linked with venous thromboembolism (adjusted odds ratio (OR 2.25), followed by neurologic immobility (OR 2.23), “other” immobility (OR 1.97) and general immobility (OR 1.76).
Although travel was the most frequently observed category of immobility, it demonstrated no evidence of a significant association with venous thromboembolism.
Dr. Kline’s team believes that “many experts would assert a risk exists between venous thromboembolism and air travel,” but they note that no study has specifically examined this issue.
Ann Emerg Med 2009;54:147-152.