Cochrane for Clinicians

Putting Evidence into Practice

Compression Stockings for Preventing Deep Venous Thrombosis in Airline Passengers


Am Fam Physician. 2022 Jan ;105(1):23.

Author disclosure: No relevant financial relationships.

Clinical Question

Are compression stockings safe and effective for the prevention of deep venous thrombosis (DVT) in airline passengers?

Evidence-Based Answer

Compression stockings are effective at reducing asymptomatic DVT in airline passengers taking flights longer than five hours in both high-risk (number needed to treat [NNT] = 37; 95% CI, 35 to 46) and low-risk (NNT = 111; 95% CI, 100 to 143) populations.1 (Strength of Recommendation: C, based on disease-oriented evidence.) It is unclear if compression stockings prevent symptomatic DVT, pulmonary embolism (PE), or death. There are no significant adverse events associated with their use.

Practice Pointers

DVT occurs through the formation of a blood clot in the deep veins, typically within the lower extremities. This can ultimately lead to a PE, a significant cause of morbidity and mortality. Prolonged periods of immobility that occur during air travel are a risk factor for the development of venous thromboembolism (VTE).2 However, symptomatic VTE (including DVT or PE) after long-distance travel is rare, with an incidence of 27 per 1 million passengers within 14 days of travel.2 Asymptomatic DVT is a finding of uncertain clinical significance and occurs in 2.4% of high-risk travelers and 1.5% of low- or medium-risk travelers.1 Risk factors for VTE with long-distance travel (greater than four hours) include active malignancy, recent surgery, pregnancy or recent postpartum state, hormone therapy, obesity, and a history of VTE.3

This Cochrane review included nine randomized trials of 2,821 patients comparing the use of bilateral, below-the-knee compression stockings vs. no stockings during flights lasting more than five hours.1 The majority of these trials were conducted in the United Kingdom. All of these studies were at risk of performance bias because blinding of the participants was not possible. The authors also noted an unclear risk of selection bias—the majority of trials did not include sufficient information on the

Author disclosure: No relevant financial relationships.


1. Clarke MJ, Broderick C, Hopewell S, et al. Compression stockings for preventing deep vein thrombosis in airline passengers. Cochrane Database Syst Rev. 2021;(4):CD004002.

2. Philbrick JT, Shumate R, Siadaty MS, et al. Air travel and venous thromboembolism: a systematic review. J Gen Intern Med. 2007;22(1):107–114.

3. Schünemann HJ, Cushman M, Burnett AE, et al. American Society of Hematology 2018 guidelines for management of venous thromboembolism: prophylaxis for hospitalized and nonhospitalized medical patients. Blood Adv. 2018;2(22):3198–3225.

These are summaries of reviews from the Cochrane Library.

This series is coordinated by Corey D. Fogleman, MD, assistant medical editor.

A collection of Cochrane for Clinicians published in AFP is available at



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