If You Can’t Upgrade, Wear Support Hose
Abstract & commentary
Synopsis: Deep venous thrombosis may occur in up to 10% of people taking flights of 8 hours or longer. Compression stockings appear to reduce this risk.
Source: Scurr JH, et al. Lancet. 2001;357:1485-1489.
Scurr and colleagues set out to learn how common deep venous thrombosis (DVT) is in "long-haul" air travelers. They were also interested in learning if compression stockings reduced the risk. To accomplish these aims, they recruited 231 people (89 men) 50 years of age or older who planned to travel economy class (aka "coach") with 2 segments of at least 8 hours duration within a 6-week period. Histories and physical examinations were performed. All eligible travelers underwent duplex ultrasonography of deep and superficial lower extremity veins before and after travel, as well as D-dimer assays, complete blood cell counts, and platelet counts. Subjects were excluded if they had a history of venous thrombosis, were taking anticoagulants, regularly wore compression stockings, or had cardiorespiratory problems or other serious disease (including malignancy). Half of the subjects were given class 1 elastic compression stockings to use during the travel. Within 2 days of the return flight, interviews, repeat duplex examination, and bloodwork were done. Thirty-one subjects were excluded because they missed 1 or more evaluations or were upgraded to first class, but these were equally distributed between the control and stocking groups, so that each group included 100 completely evaluated patients. Twelve (10%) of the passengers not wearing stockings developed asymptomatic calf DVT, but none of the passengers wearing compression stockings did. Four of those wearing stockings developed superficial thrombophlebitis in pre-existing varicose veins, but none of the no-stocking group did.
Comment by Barbara A. Phillips, MD, MSPH
This paper is remarkable for a couple of reasons. It is the first study to look prospectively at the incidence of DVT in a well-defined population of long distance air travelers. This was an older group (³ 50 years of age) and the flights were quite long (8 hours), but a 10% risk of calf DVT still seems strikingly high. While it is true that asymptomatic calf vein thrombosis is probably not a major risk to health, 10-20% of them extend proximally.1 Further, pulmonary embolus occurs in about 10% of those with isolated calf vein thrombosis.2
Another notable finding of this study is that simple below-the-knee graduated elastic stockings appeared to eliminate the risk of calf vein DVT (though they may have exacerbated superficial phlebitis associated with varicose veins) in this group of subjects.
Our "frequent flyer" patients are likely to be aware of these issues and to ask our advice, because the market is already at work. In the back pages of my favorite airline’s slick in-flight magazine is an ad that begins: "Economy Class Syndrome." You guessed it. It offers "stylish, medically correct graduated compression over-the calf socks in dress or casual colors at factory low prices." At this point, I’d have to say there is some evidence to support the use of these socks on long distance flights.
For those of you who have been wondering if it’s worth it to upgrade to first class on long flights, the answer appears to be yes.
1. Kazmers A, Groehn H, Meeker C. Am Surg. 1999;65: 1124-1127.
2. Meissner MH, et al. J Vasc Surg. 1997;26:749-756.