Air travel and fatal pulmonary embolism

Summary

Although long-distance air travel is commonly regarded as a risk factor for venous thromboembolism, the risk of clinically important events has not been well defined. We estimated the absolute risk of dying from pulmonary embolism following longdistance air travel in a national population-based descriptive study of 121 men and women who were aged 15–59 years (the age range in which the majority of international arrivals are found) and whose underlying cause of death was certified as codes 415.1, 451, or 453 of the International Classification of Diseases (ninth revision). Eleven cases had undertaken longdistance air travel in the four weeks before the onset of the fatal episode. The estimated risks of fatal pulmonary embolism following a flight of at least three hours’ duration were 0.5 (95% CI 0.2–1.2) and 0.6 (95% CI 0.2–1.4) per million arrivals for overseas visitors and New Zealand residents, respectively. For air travel of more than eight hours’ duration, the risk in New Zealand residents was 1.3 (95% CI 0.4–3.0) per million arrivals. We also conducteda case-control study based on those cases who were normally resident in New Zealand and registered on the electoral roll (n=99). For each case, four controls matched for sex, age, and electorate, were randomly selected from the electoral roll. In the key analysis (based on 88 cases and 334 controls), the adjusted odds ratio for travellers who had flown for more than eight hours was 7.9 (95% CI 1.1–55.1) compared with those who did not undertake a long-distance flight. Longdistance air travellers have a higher risk of dying from pulmonary embolism than non-travellers, but the absolute risk in people aged 15–59 years appears to be very small.

Keywords

Clinical / epidemiological studies - pulmonary embolism

• References

• 1 Goldhaber SZ. Pulmonary embolism. Lancet 2004; 363: 1295-305.
• 2 Chee YL, Watson HG. Air travel and thrombosis. Br J Haematol 2005; 130: 671-80.
• 3 Kelman CW, Kortt MA, Becker NG. et al. Deep vein thrombosis and air travel: record linkage study. BMJ 2003; 327: 1072-6.
• 4 World Health Organization Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception. A multinational case-control study of cardiovascular disease and steroid hormone contraceptives. Description and validation of methods. J Clin Epidemiol 1995; 48: 1513-47.
• 5 Ferrari E, Chevallier T, Chapelier A. et al. Travel as a risk factor for venous thromboembolic disease. A case-control study. Chest 1999; 115: 440-4.
• 6 Kraaijenhagen RA, Haverkamp D, Koopman MMW. et al. Travel and risk of venous thrombosis. Lancet 2000; 356: 1492-3.
• 7 Arya R, Barnes JA, Hossain U. et al. Long-haul flights and deep vein thrombosis: a significant risk only when additional factors are also present. Br J Haematol 2002; 116: 653-4.
• 8 Samama M. An epidemiologic study of risk factors for deep vein thrombosis in medical outpatients. Arch Intern Med 2000; 160: 3415-20.
• 9 Hennekens GH, Buring JE. Epidemiology in Medicine. Philadelphia: Lippincott Williams and Wilkins; 1987
• 10 Statistics New Zealand. Tourism and migration. Wellington: Statistics New Zealand; 2001
• 11 Galbraith C, Jenkin G, Davis P. et al. New Zealand Socio-economic Index 1996. User’s Guide. Wellington: Statistics New Zealand; 2003
• 12 New Zealand Health Information Service. A guide to certifying causes of death: Ministry of Health. 2001
• 13 Rosendaal FR. Air travel and thrombosis. Pathophysiol Haemost Thromb 2002; 32: 341-2.
• 14 Martinelli I, Taioli E, Battaglioli T. et al. Risk of venous thromboembolism after air travel: Interaction with thrombophilia and oral contraceptives. Arch Intern Med 2003; 163: 2771-4.
• 15 Schwarz T, Siegert G, Oettler W. et al. Venous thrombosis after long-haul flights. Arch Intern Med 2003; 163: 2759-64.
• 16 Lapostolle F, Surget V, Borron SW. et al. Severe pulmonary embolism associated with air travel. N Engl J Med 2001; 345: 779-83.
• 17 Arya R, Cohen AT. Long haul flights and deep vein thrombosis: Who is at risk?. Br J Haematol 2003; 120: 368.
• 18 Perez-Rodriguez E, Jimenez D, Diaz G. et al. Incidence of air travel-related pulmonary embolism at the Madrid-Barajas Airport. Arch Intern Med 2003; 163: 2766-70.
• 19 Hosoi Y, Geroulakos G, Belcaro G. et al. Characteristics of deep vein thrombosis associated with prolonged travel. Eur J Vasc Endovasc Surg 2002; 24: 235-8.
• 20 Hertzberg SR, Roy S, Hollis G. et al. Acute symptomatic pulmonary embolism associated with long haul air travel to Sydney. Vasc Med 2003; 08: 21-3.
• 21 Scurr JH, Machin SJ, Bailey-King S. et al. Frequency and prevention of symptomless deep-vein thrombosis in long-haul flights: A randomised trial. Lancet 2001; 357: 1485-9.
• 22 Belcaro G, Geroulakos G, Nicolaides AN. et al. Venous thromboembolism from air travel: The LONFLIT Study. Angiology 2001; 52: 369-74.
• 23 Cesarone MR, Belcaro G, Nicolaides AN. et al. Venous thrombosis from air travel: The LONFLIT3 Study. Prevention with aspirin vs low-molecular-weight heparin (LMWH) in high-risk subjects: A randomized trial. Angiology 2002; 53: 1-6.
• 24 Belcaro G, Cesarone MR, Shah SSG. et al. Prevention of edema, flight microangiopathy and venous thrombosis in long flights with elastic stockings. A randomized trial. The LONGFLIT 4 Concorde Edema- SSL Study. Angiology 2002; 53: 635-45.
• 25 Cesarone MR, Belcaro G, Errichi BM. et al. The LONGFLIT4-Concorde Deep Venous Thrombosis and Edema Study: Prevention with travel stockings. Angiology 2003; 54: 143-54.
• 26 Cesarone MR, Belcaro G, Nicolaides AN. et al. Prevention of venous thrombosis in long-haul flights with Flite Tabs: The LONGFLIT-FLITE Randomized, Controlled Trial. Angiology 2003; 54: 531-9.
• 27 Hughes RJ, Hopkins RJ, Hill S. et al. Frequency of venous thromboembolism in low to moderate risk long distance air travellers: the New Zealand Air Traveller’s Thrombosis (NZATT) study. Lancet 2003; 362: 2039-44.