26 for side effects
The numbers presented are from the best studies that are currently available. Some of these studies will NEVER be repeated and so this is all we'll ever have to go on. There will be continued study in some areas and we aim to incorporate this forward into our site. We're constantly monitoring the literature for updates (if you think there is something we've missed, email us!). The conclusions we draw are a best estimate, folks. We've presented what we think is the closest thing to the truth about this intervention, but our data is only as good as the studies that underlie it — and often, the studies aren't as complete or as good as we'd like. We present one number here for the NNT, but please realize this is an estimate and there is a range for what this intervention can offer a given person. That range will depend upon the person's spectrum of disease (mild/moderate/severe), their demographic, their subtype of disease, the setting of the intervention, their general health, and literally thousands of other variables. Using these numbers in practice means taking a number of large leaps about all of these variables, and also about the veracity of the underlying research. Therefore, as with any 'high quality' data, the application of data requires a doctor's expertise and deliberate consideration.
In Summary, for those who received the stockings:
- 100% saw no benefit
- 0% were helped by preventing DVT, PE or death
- 4% were harmed by stocking side effects
In Other Words:
- None were helped
- 1 in 26 were harmed (skin breakdown, ulcers, blisters skin necrosis)
Where We Get The Numbers:
Source: Naccarato M, Chiodo Grandi F, Dennis M, Sandercock PAG. Physical methods for preventing deep vein thrombosis in stroke (Review). Cochrane Database Syst Rev. 2010. Issue 8. Art. No.: CD001922. DOI: 10.1002/14651858.CD001922.pub3
The CLOTS Trials Collaboration Effectiveness of thigh-length graduated compression stockings to reduce the risk of deep vein thrombosis after stroke (CLOTS trial 1): a multicentre, randomised controlled trial. Lancet 2009; 373: 1958–65
Efficacy Endpoints: Deep Vein Thrombosis (DVT), PE, Death
Harm Endpoints: Skin breakdown, blisters, ulcers, skin necrosis
Narrative: It has long been observed that hospitalized patients are at increased risk for developing a DVT. Venous stasis and lack of mobility are known risk factors for developing venous thromboemboli. It has been hypothesized that compression stockings, by compressing superficial veins, cause increased blood flow through the deep veins in the extremities, decreasing venous stasis and DVT.
The Cochrane review identified two trials comparing GCS (graduated compression stockings) with routine care for DVT prophylaxis including a total of 2615 patients. The larger is the 2009 CLOTS trial, with 2518 (96%) of the subjects included in the review. Approximately 12% of subjects in each group were on anticoagulants in this study and the review showed no difference in DVT, PE, or death between the control and the study group, regardless of anticoagulation status. The stocking group, however did have an increased risk of harm including skin breakdown, blisters, ulcers, or skin necrosis.
Caveats: The purpose of preventing DVT is to prevent the life threatening or physiologically uncomfortable symptoms of either DVT or pulmonary embolism. The great bulk of the included trials did not measure these outcomes, making it impossible to know if preventing DVTs has an important impact on patient-oriented outcomes. Large, high quality, well-powered trials that closely track both the adverse effects of stockings (discomfort, etc.) and clinically important events related to venous thromboembolism are badly needed.
All of the included trials involved patients with acute stroke as the reason for their hospitalization, and none of the studies included low risk patients. Consequently, firm conclusions from these data can only be drawn regarding GCS for stroke patients.
It should be noted that there is relatively robust data to suggest that GCS appear to be of benefit when used for surgical patients in the post-operative inpatient setting. For more information, please refer to related entries on this topic.
Author: Viral Patel, MD
Published/Updated: January 30, 2012
