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Travel and Venous Thromboembolism

Results of a meta-analysis showed a significant elevation in risk that increased with the duration of the journey.

Concern about travel-related venous thromboembolism (VTE) has recently attracted public attention. To examine the risk for VTE in travelers, these investigators conducted a literature analysis of 14 studies (2 cohort, 11 case-control, and 1 case-crossover) with a total of 4055 cases of VTE. The mode of travel in the studies varied (5 air only, 9 air or surface), and the outcomes evaluated were deep venous thrombosis alone in seven, pulmonary embolism (PE) or DVT in five, and PE alone in two.

Compared with nontravelers, the pooled relative risk for VTE in travelers across all studies was 2.0 (P<0.001). However, significant heterogeneity resulted from differences in study design — specifically, in the selection criteria for controls. No evidence was found for heterogeneity based on study location, travel duration, duration of follow-up after travel, source of control population, method of exposure assessment, or number of confounders included in multivariate analysis. The pooled risk estimate was somewhat higher for air travel (RR, 2.2) than for surface travel (RR, 1.4). When duration of travel was assessed, the risk for VTE rose at a statistically significant 18% per 2-hour increase in travel duration.

Comment: In this literature-review study, the risk for venous thromboembolism in travelers was twice as high as in nontravelers. It must be cautioned that although the relative risk for VTE was high, the absolute risk has been estimated to be 1 case per 4600 (or more) airline flights. For now, hydration and ambulation remain the best interventions for preventing travel-related VTE.

— Joel M. Gore, MD

Published in Journal Watch Cardiology August 12, 2009

Citation(s):

Chandra D et al. Travel and risk for venous thromboembolism. Ann Intern Med 2009 Aug 4; 151:180.

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