Acute deep venous thrombosis (DVT) is associated with leg pain and discomfort. Elastic compression stockings (ECS) have the potential to improve DVT-related leg pain by reducing the diameter of distended veins, increasing venous blood flow and reducing venous hypertension. To date, however, the effect of ECS on DVT-related leg pain has not been studied. In the SOX Trial, a randomized trial of active ECS vs. placebo ECS to prevent the post-thrombotic syndrome, we measured leg pain intensity at baseline and at several time-points during follow-up.
In a secondary, non-prespecified analysis of the SOX Trial, to determine whether active ECS, compared with placebo (sham) stockings, are effective to reduce leg pain associated with acute proximal DVT.
We did a multicenter (24 centres in Canada and U.S.) randomized placebo controlled trial of active ECS vs. placebo ECS after a first, symptomatic proximal DVT. Active ECS were knee length, 30-40 mm Hg (Class II) graduated ECS. Placebo ECS were manufactured to appear identical to active ECS but lacked therapeutic compression. Study stockings were worn on the DVT-affected leg daily and continued for up to 2 years. Exclusion criteria were >10 days since DVT diagnosis, not planned to be treated with anticoagulants, known peripheral arterial disease or limb phlegmasia, anticipated lifespan < 6 months, inability of patient or caregiver to apply ECS, thrombolysis to treat DVT, geographically inaccessible for follow-up visits or unable to give informed consent. Leg pain intensity was assessed on a 10-point Visual Analog Scale (0, no pain; 10, worst possible pain) via patient self-report at baseline, 14 days, 1 month and 60 days after randomization. We compared mean pain scores at each time point in the active ECS vs. placebo ECS groups using t-tests. We repeated this analysis, restricted to patients who reported daily stockings use at the 1 month visit (the first visit at which frequency of stocking use was assessed). We conducted pre-specified subgroup analyses by age, sex, and extent of DVT. Results are presented as mean difference (95% confidence interval [CI]) in pain intensity score between groups. All statistical tests were 2-sided and significance was set at P<0.05.
410 patients were randomized to active ECS and 396 to placebo ECS. One and 2 patients, respectively, were found to be ineligible soon after randomization and excluded from the analysis. Mean time from DVT diagnosis to randomization was 4.7 days. Baseline characteristics were similar in the 2 groups (60% male, mean age 55.1 years, highest proximal extent of DVT was iliac or femoral vein in 70% and popliteal vein in 30%, 87% were out-patients). Pain scores diminished over time in both groups. There were no differences between groups in pain scores at any time-point (Table), and no evidence for subgroup interaction by age category, sex or anatomical extent of DVT (not shown).
In a large randomized placebo-controlled trial in patients with symptomatic proximal DVT, leg pain improved at each follow-up visit to a similar degree in patients randomized to active ECS and placebo ECS, and we did not find evidence for benefit of active ECS to reduce pain associated with acute proximal DVT. As our first follow-up assessment was 14 days after DVT, we were unable to evaluate if active ECS had a beneficial or detrimental effect on pain scores during the first 2 weeks after DVT.
No relevant conflicts of interest to declare.