RCT sets aside a common practice
Kahn et al1 conducted a randomized, placebo-controlled trial of active versus placebo ECS in patients from 24 centers in the United States and Canada who’d had an ultrasound-confirmed proximal DVT (in the popliteal or more proximal deep leg vein) within the previous 14 days. Most patients received standard anticoagulation therapy to treat their DVT (five to 10 days of heparin and three to six months of warfarin). Patients were excluded if they had received thrombolytics, had arterial claudication, had a life expectancy of less than six months, were unable to put on ECS due to physical disabilities or allergy, or were unable to participate in follow-up visits.
Patients were randomly assigned to wear active (30 to 40 mm Hg graduated) ECS or identical-looking placebo ECS (< 5 mm Hg compression at the ankle) for two years. Providers, study personnel and statisticians, and patients were all blinded to treatment allocation. Patients were asked to wear the stocking on the affected leg each day from waking until bedtime.
Follow-up occurred at one, six, 12, 18, and 24 months. The primary outcome was cumulative incidence of PTS diagnosed at six months or later using the Ginsberg criteria of ipsilateral pain and swelling of at least one month’s duration.8 Secondary outcomes included severity of PTS, leg ulcers, recurrence of venous thromboembolism (VTE), death, adverse events, venous valvular reflux, and quality of life (QOL). Outcomes were measured objectively through use of a validated scale (the Villalta scale) for PTS severity and two questionnaires to assess QOL.9-11
There were 409 patients in the ECS group and 394 in the placebo group. Baseline characteristics, including BMI, VTE risk factors, and anticoagulation treatment regimens, were similar between groups. The average age of participants in the study group was 55.4 years and in the placebo group, 54.8 years. Men comprised 62.4% of the active group and 57.9% of the placebo group. Approximately 90% of the participants in both groups were white.
At one month, approximately 95% of participants in both groups used the stockings; at 24 months, that was reduced to a little less than 70%. The percentage of people who used the stockings for at least three days per week was similar in both groups.
The cumulative incidence of PTS during follow-up was 14.2% in the active group and 12.7% in the placebo group (hazard ratio, 1.13). There were no differences in any of the secondary outcomes. Prespecified subgroup analyses found that age, BMI, and severity of DVT had no effect on outcomes. There was a marginal benefit for ECS for women versus men, but this does not likely reflect a true difference because the confidence intervals surrounding the hazard ratios for men and women overlapped and crossed the null value.
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