A Cochrane review included 11 studies with a total of 2 906 subjects. Nine studies compared wearing stockings on both legs versus not wearing them. Eight (n=1598) included people judged to be at low or medium risk and two included high risk participants. One study (n=35) compared wearing a stocking on one leg for the outbound flight and on the other leg on the return flight. Nine flights lasted at least 7 hours and one over 5 hours. No deaths, pulmonary emboli or symptomatic deep vein thrombosis (DVT) were reported. Wearing stockings reduced symptomless DVTs (hifh-quality evidence), superficial vein thrombosis (moderate-quality evidence), and leg oedema (low-quality evidence) (table ). No significant adverse effects were reported.
| Outcome Follow-up immediately post flight to 48 hours | Relative effect (95% CI) | Assumed risk - No compression stockings | Corresponding risk - Intervention - Compression stockings (95% CI) | No of participants (studies) |
|---|---|---|---|---|
| Symptomless DVT: low risk population | OR 0.10 (0.04 to 0.25) | 10 / 1000 | 1 / 1000 (0 to 3) | 2637 (9) |
| Symptomless DVT: high risk population | OR 0.10 (0.04 to 0.25) | 30 / 1000 | 3 / 1000 (1 to 8) | 2637 (9) |
| Superficial vein thrombosis | OR 0.45 (0.18 to 1.13) | 13 per 1000 | 6 per 1000 (2 to 15) | 1804 (8) |
| Oedema: Immediately post flight, scale 0 to 10 (0 = no oedema) | - | 6 to 9 | on average 4.7 lower (4.9 lower to 4.5 lower) | 1246 (6) |