Compression Stockings to Prevent Post-Thrombotic Syndrome: A Randomised Placebo-Controlled Trial

Study Questions:

What is the efficacy of elastic compression stockings (ECS) to prevent post-thrombotic syndrome?


The SOX trial investigators conducted a multicenter, randomized, placebo-controlled trial of active versus placebo ECS used for 2 years to prevent post-thrombotic syndrome (PTS) after a first proximal deep venous thrombosis (DVT) in centers in Canada and the USA. Patients were randomly assigned to study groups with a web-based randomization system. Patients presenting with a first symptomatic, proximal DVT were potentially eligible to participate. They were excluded if the use of compression stockings was contraindicated, they had an expected lifespan of less than 6 months, geographical inaccessibility precluded return for follow-up visits, they were unable to apply stockings, or they received thrombolytic therapy for the initial treatment of acute DVT. The primary outcome was PTS diagnosed at 6 months or later using Ginsberg’s criteria (leg pain and swelling of ≥1 month duration). The authors used a modified intention-to-treat Cox regression analysis, supplemented by a prespecified per-protocol analysis of patients who reported frequent use of their allocated treatment.


From 2004 to 2010, 410 patients were randomly assigned to receive active ECS, and 396 assigned to placebo ECS. The cumulative incidence of PTS was 14.2% in active ECS versus 12.7% in placebo ECS (hazard ratio adjusted for center, 1.13; 95% confidence interval, 0.73-1.76; p = 0.58). Results were similar in a prespecified per-protocol analysis of patients who reported frequent use of stockings.


The authors concluded that ECS did not prevent PTS after a first proximal DVT.


The study findings show that wearing a graduated ECS did not reduce the incidence of PTS at 2 years in patients with a first proximal DVT, compared with wearing placebo stockings. Similarly, ECS did not affect the occurrence of venous ulcers, rate of recurrent venous thromboembolism, prevalence of venous valvular reflux at 12 months, or generic or venous disease specific quality of life. These findings were consistent across subgroups defined by age, body mass index, and extent of DVT. Overall, the results do not support routine wearing of ECS after DVT to prevent PTS.

Clinical Topics: Vascular Medicine

Keywords: Thrombolytic Therapy, Follow-Up Studies, Stockings, Compression, Canada, Postthrombotic Syndrome, Venous Thrombosis, Pain, Leg, Regression Analysis

< Back to Listings