Table 2. Details of the results reported by the randomized clinical trials included in the systematic review.
| Author (year) | Outcome | Other results |
|---|---|---|
| DVT/PTE prophylaxis | ||
| Scurr et al. (2001)17 | After the flights, 12 passengers who had not worn GCS developed symptomless DVT in the calf that was detected in duplex ultrasonographic examinations (10%; 95% confidence interval [CI] 4.8–16.0%]. None of the 115 passengers (95%CI 0–3.2%) who did wear GCS exhibited DVT. Four people who did wear GCS developed superficial thrombophlebitis of varicose veins (3%; 1.0-0.8%). None of the control group members developed superficial thrombophlebitis (1%; 0–3%,). | 14 (7%) of the 200 participants were heterozygous for factor V Leiden (n = 11) or prothrombin (n = 4) gene mutations. |
| One person who had both genetic mutations had an episode of thrombophlebitis. | ||
| Two passengers with symptomless DVT were factor V Leiden positive. | ||
| Complete blood count, platelet counts, and D-dimer assays did not provide prognostic information. | ||
| Only two passengers took medications, in addition to their usual medications. | ||
| Belcaro et al. (2002)18 | PART I: GCS group: none of the participants had DVT or superficial thromboses. Control group: 4 (2.2%) had DVT (2 popliteal and 2 in proximal tibial veins). In total, 3.35% (n = 6) subjects had a thrombotic event (p < 0.002). | PART I: Edema: After the flight, edema scores were 6.74+3.1 in the control group, compared to 2.16+1.1 in the GCS group, 2.9 times lower than in the control group (p < 0.005). Around 80% of the individuals in the control group had increases in ankle circumference and volume that was evident on examination and associated with some degree of discomfort. |
| PART II: GCS group: none of the participants had DVT or superficial thromboses. Control group: 3 had DVT and 3 had superficial vein thromboses (SVT). In total, 4.2% (n = 6) subjects had a thrombotic event (p < 0.02). | PART II: Edema: After the flight, edema scores were 8.08+2.9 in the control group, compared to 2.56+1.56 in the GCS group, with p < 0.05. | |
| Cesarone et al. (2003)19 | PART I: None of the participants had DVT or superficial thromboses in the stockings group or the control group. | PART I: Edema: After the flight, edema scores were 6.9+2.0 in the control group, compared to 2.3+1.0, in the GCS group, three times lower than in the control group (p < 0.05). At least 89% of the individuals in the control group had increases in ankle circumference and volume that were evident on examination and associated with some degree of discomfort. Control of edema with GCS was clear, considering both parametric (circumference and volume) and nonparametric (analog scale) data. |
| PART II: No DVT were observed in the stockings group. In the control group, two individuals had popliteal DVT (limited, length > 2 cm, asymptomatic) and two had superficial thrombosis (thrombi in one of the long branches of the saphenous vein, both below the knee), with p < 0.02. Four individuals (6%) in the control group exhibited thrombotic events. The incidence of DVT was 3%. | PART II: Edema: After the flight, edema scores were 7.94+2.0 in the control group, compared to 3.3+1.2 in the GCS group. In the GCS group, the hourly increase in score was 0.17 on 7-hour flights and 0.19 on 11-hour flights, compared with 0.82 and 0.63 in control group (on flights lasting 7 and 11 hours, respectively). In the GCS group, edema scores were 3.2+0.8 at enrollment and 6.2+1.4 after the 7-hour flight. In the control group, scores were 3.0+0.9 at enrollment and 9.6+0.2 at the end of the flight (p < 0.05). | |
| Overview: Considering DVT, the difference between control and treatment groups was significant (p < 0.05) - 2/138 = 1.44% vs. 0/138 = 0%. | ||
| Cesarone et al. (2003)20 | PART I: None of the 97 control group subjects who completed the study had DVT or superficial thrombosis. | PART I: Edema levels at enrollment were comparable in both groups. After the flight, edema scores were 6.4+1.3 in the control group, compared to 2.4+1.0 in the GCS group, 2.6 times lower than in the control group (p < 0.05). In the control group, 83% of the subjects had increases in ankle circumference and volume that was evident on examination and associated with some degree of discomfort. |
| PART II: None of the GCS group participants had deep or superficial thrombosis. No thrombotic events were observed in any of the 71 control group members who completed the study. | PART II: Edema levels at enrollment were comparable in both groups (1.1). After the flight, edema scores were 8.9+2.0 in the control group, compared to 2.56+1.3 in the GCS group (p < 0.05). Control of edema with GCS was clear, even after 11-hour flights, considering circumference, volume, and analog scale lines. At the end of the flight, a limited quantity of edema was observed in all subjects who wore GCS. Significant edema was observed in those who did not wear GCS. | |
| Belcaro et al. (2003)14 | In the treatment group, just one limited, distal, DVT was observed (0.4 cm in length, soleus vein, 0.97%). In the control group, six subjects (5.8%) had DVT and there was no superficial thrombosis. The difference in DVT incidence was significant (p < 0.0025). | The intention-to-treat analysis detected 18 failures in the control group (12 lost to follow-up + six thromboses), out of 114 individuals (15.6%), vs. eight failures (7.3%) in the treatment group, with p < 0.05. All thrombotic events were totally asymptomatic. The three women who had thrombotic events in the control group and the only case in the GCS group had all been taking low dose oral contraceptives for at least 12 months before the flight. |
| Hagan et al. (2008)21 | When wearing GCS, there was a reduction in edema at the ankle compared with not wearing GCS (mean difference: -0.19 cm; 95%CI, -0.33 to -0.065 cm; p = 0.012). | When wearing GCS, participants had a 60% improvement in their classification of leg pain at the end of the flight, a 50% improvement in their classification of leg discomfort, and 45% improvement in their classification of leg edema. There was also an 18% improvement in energy level, a 13% improvement in alertness, and a 12% improvement in concentration capacity. |
| Charles et al. (2011)13 | At 120 minutes, peak systolic velocity was 24% greater with treatment, with a difference of 0.34 cm/s (95%CI, 0.12 to 0.56, p = 0.004). There was a reduction in the risk of VTE associated with long-haul journeys. Peak systolic velocity was 0.35 cm/s (95%CI, 0.22 to 0.49, p < 0.001) greater when stockings were worn. The overall difference between legs with and without stockings for the calf circumference measurement at 120 minutes was 7.9 mm (95%CI, –13.3 to -2.4, p = 0.011). The below-the-knee graduated compression stocking increased venous blood flow in the lower limbs during prolonged immobility in the sitting position. | The stocking was associated with a reduction in edema in the leg, ankle and calf, suggesting a potential utility for edema of the lower limbs, secondary to chronic venous insufficiency and lymphedema. Peak systolic velocity was also significantly higher at 30 and 60 minutes when wearing stockings compared with not wearing them. Mean flow velocity and total flow volume were greater at 60 and 120 minutes when wearing the stocking. |
| Olsen et al. (2019)22 | There was no significant difference for DVT/PTE. | The difference in ankle circumference was 5 mm greater after the flight compared to before the flight, IQR = 0–9, p = 0.001. Legs wearing GCS had a 2 mm median reduction in ankle circumference (p = 0.004) during the flight, whereas legs without GCS had an average increase of 2 mm (p = 0.01). The difference between calf circumferences before and after the flight was 5 mm, IQR = 1–12, p < 0.001. After the flight, legs wearing compression stocking had a 3mm reduction in calf circumference (p = 0.007), whereas calf circumference of legs not wearing GCS increased by a median of 3 mm (p = 0.02). |
| Pain and Discomfort: There was no significant difference in pain or discomfort in the legs after the flight compared with before the flight. Although the visual analog pain scale did not increase after the flight, there was an increase in the visual analog discomfort scale of 1 mm in legs wearing GCS (p = 0.005). |
GCS = Graduated compression stockings; DVT = deep venous thrombosis; VTE = venous thromboembolism; PTE = pulmonary thromboembolism; IQR = interquartile range.