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KSR Number: KSRA84548

Graduated compression stockings for prevention of deep vein thrombosis

  • Cochrane Database Syst Rev 2018, 11, CD001484, 10.1002/14651858.CD001484.pub4
  • Full report

Risk of Bias Assessment

Overall summary: High risk of bias in the review

Bottom Line

Current evidence suggests that graduated compression stockings (GCS) may reduce the risk of deep vein thrombosis (DVT) and proximal DVT in patients hospitalised for any reason, for surgical reasons or for specific orthopaedic surgery compared to no GCS. Additionally, very low-quality evidence suggests that GCS may reduce the risk of developing pulmonary embolism. However, these conclusions should be interpreted with caution, since methodological weaknesses in the original review (which was expanded upon in this update) mean that reviewer error and bias cannot be ruled out. Further high quality trials focusing on the use of GCS in patients with malignancy, a past history of DVT or hypercoagulable states are required; and further evidence is required to analyse the complications that may be associated with GCS use.

Risk of Bias Assessment

Overall summary High risk of bias in the review

High

While two reviewers were involved in study selection for the update search, the original study selection was performed by only one or two reviewers, meaning reviewer error and bias across the full systematic review cannot be ruled out.

A. Did the interpretation of findings address all of the concerns identified in Domains 1 to 4? Probably no
B. Was the relevance of identified studies to the review's research question appropriately considered? Probably yes
C. Did the reviewers avoid emphasizing results on the basis of their statistical significance? Probably yes
Risk of bias in the review High

Details of Review

Number of studies 20
Number of participants 1681
Last search date 12th June 2018
Review type Intervention
Objective To assess the effectiveness and safety of graduated compression stockings in preventing deep vein thrombosis in various groups of hospitalised patients.
Population Patients of any age or gender who were hospitalised for any condition except stroke
Interventions Graduated compression stockings
Comparator No prophylaxis; no stockings but paired with another method of deep vein thrombosis prophylaxis applied to both the intervention and control groups (e.g. aspirin, heparin)
Outcome Primary outcomes: diagnosis of deep vein thrombosis (DVT), either all DVT or proximal DVT.

Secondary outcomes: diagnosis of pulmonary embolism; complications and adverse effects arising from the use of graduated compression stockings.
Study design Randomised controlled trials

Results

In terms of the incidence of deep vein thrombosis (DVT), pooled analysis reported a reduction in the incidence of DVT following the use of graduated compression stockings (GCS) in patients hospitalised for any reason (peto odds ratio [pOR] 0.35, 95% confidence interval [CI] 0.28 to 0.43; 20 studies, n=2853 legs or patients), patients hospitalised for any type of surgical procedure (pOR 0.35, 95% CI 0.28 to 0.44; 19 studies, n=2693 legs or patients) or patients hospitalised for orthopaedic surgery (pOR 0.47, 95% CI 0.32 to 0.68; 6 studies, n=598 legs or patients) compared to no GCS. A single study also reported a reduction in the incidence of DVT for GCS compared to no GCS in patients hospitalised for myocardial infarctions (pOR 0.12, 95% CI 0.03 to 0.51; 1 study, n=160 legs).

In terms of the incidence of proximal DVT, pooled analysis reported a reduction in the incidence of proximal DVT following the use of GCS in patients hospitalised for any reason (pOR 0.26, 95% CI 0.13 to 0.53; 8 studies, n=1035 legs or patients) or patients hospitalised for any type of surgical procedure (pOR 0.26, 95% CI 0.13 to 0.53; 7 studies, n=875 legs or patients) compared to no GCS.

In terms of the incidence of pulmonary embolism (PE), pooled analysis reported a reduction in the incidence of PE following the use of GCS in patients hospitalised for any reason (pOR 0.38, 95% CI 0.15 to 0.96; 5 studies, n=569 legs or patients) or patients hospitalised for any type of surgical procedure (pOR 0.38, 95% CI 0.15 to 0.96; 5 studies, n=569 legs or patients) compared to no GCS.

In terms of adverse effects, some participants were reported to remove GCS due to discomfort or a poor fit; however, adverse effects and complications were not routinely reported quantitatively in included studies.

Full Risk of Bias Assessment

The research objective was clearly stated and appropriate inclusion criteria were defined. No restrictions were imposed based on study characteristics or sources of information.

1.1 Did the review adhere to pre-defined objectives and eligibility criteria? Probably yes
1.2 Were the eligibility criteria appropriate for the review question? Probably yes
1.3 Were eligibility criteria unambiguous? Probably yes
1.4 Were all restrictions in eligibility criteria based on study characteristics appropriate (e.g. date, sample size, study quality, outcomes measured)? Probably yes
1.5 Were any restrictions in eligibility criteria based on sources of information appropriate (e.g. publication status or format, language, availability of data)? Probably yes
Concerns regarding specification of study eligibility criteria Low

As an update to previous searches, the Cochrane Vascular Specialised Register, CENTRAL, Medline (Ovid; 2017-2018 only), Embase (Ovid; 2017-2018 only), AMED (OVID; 2017-2018 only) and CINAHL (EBSCO; 2017-2018 only) databases were searched. WHO ICTRP and ClinicalTrials.gov were also searched for relevant studies. The reference lists of the included studies were searched to identify any additional relevant studies. The search strategy was reported and appeared adequate. There were no restrictions based on date, publication format or language. In this update, two reviewers were involved in study selection, and disagreements were resolved by consensus; however, for the original systematic review, only a single reviewer was involved in study selection during the title/abstract phase to exclude obvious exclusions, with a second reviewer being consulted in cases of uncertainty; and for the remaining records (which were not obvious excludes), two reviewers were independently involved in study selection, and any disagreements were resolved by discussion with a third reviewer.

2.1 Did the search include an appropriate range of databases/electronic sources for published and unpublished reports? Probably yes
2.2 Were methods additional to database searching used to identify relevant reports? Probably yes
2.3 Were the terms and structure of the search strategy likely to retrieve as many eligible studies as possible? Probably yes
2.4 Were restrictions based on date, publication format, or language appropriate? Probably yes
2.5 Were efforts made to minimise error in selection of studies? Probably no
Concerns regarding methods used to identify and/or select studies High

One reviewer performed data extraction and a second reviewer cross-checked the data. Sufficient individual study characteristics were provided to allow for the interpretation of results. Relevant study results appeared to have been extracted. The methodological quality for all included studies was assessed using the Cochrane risk of bias tool for randomised controlled trials. Two review authors were involved in independently assessing the risk of bias.

3.1 Were efforts made to minimise error in data collection? Probably yes
3.2 Were sufficient study characteristics considered for both review authors and readers to be able to interpret the results? Probably yes
3.3 Were all relevant study results collected for use in the synthesis? Probably yes
3.4 Was risk of bias (or methodological quality) formally assessed using appropriate criteria? Probably yes
3.5 Were efforts made to minimise error in risk of bias assessment? Probably yes
Concerns regarding methods used to collect data and appraise studies Low

The synthesis appeared to include all relevant studies. The method of analysis was explained and appeared appropriate. Heterogeneity was assessed and found to be low to moderate for all outcomes. Sensitivity analyses were performed to check the robustness of the study results. Publication bias was assessed using visual inspection of funnel plots. Bias in the primary studies was addressed while interpreting the findings.

4.1 Did the synthesis include all studies that it should? Probably yes
4.2 Were all pre-defined analyses reported or departures explained? Probably yes
4.3 Was the synthesis appropriate given the degree of similarity in the research questions, study designs and outcomes across included studies? Probably yes
4.4 Was between-study variation minimal or addressed in the synthesis? Probably yes
4.5 Were the findings robust, e.g. as demonstrated through funnel plot or sensitivity analyses? Probably yes
4.6 Were biases in primary studies minimal or addressed in the synthesis? Probably yes
Concerns regarding synthesis and findings Low

Abstract

Abstract - Background Hospitalised patients are at increased risk of developing deep vein thrombosis (DVT) in the lower limb and pelvic veins, on a background of prolonged immobilisation associated with their medical or surgical illness. Patients with DVT are at increased risk of developing a pulmonary embolism (PE). The use of graduated compression stockings (GCS) in hospitalised patients has been proposed to decrease the risk of DVT. This is an update of a Cochrane Review first published in 2000, and last updated in 2014. Objectives To evaluate the effectiveness and safety of graduated compression stockings in preventing deep vein thrombosis in various groups of hospitalised patients. Search methods For this review the Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), and trials registries on 21 March 2017; and the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE Ovid, Embase Ovid, CINAHL Ebsco, AMED Ovid , and trials registries on 12 June 2018. Selection criteria Randomised controlled trials (RCTs) involving GCS alone, or GCS used on a background of any other DVT prophylactic method. We combined results from both of these groups of trials. Data collection and analysis Two review authors (AS, MD) assessed potentially eligible trials for inclusion. One review author (AS) extracted the data, which a second review author (MD) cross‐checked and authenticated. Two review authors (AS, MD) assessed the methodological quality of trials with the Cochrane 'Risk of bias' tool. Any disagreements were resolved by discussion with the senior review author (TL). For dichotomous outcomes, we calculated the Peto odds ratio and corresponding 95% confidence interval. We pooled data using a fixed‐effect model. We used the GRADE system to evaluate the overall quality of the evidence supporting the outcomes assessed in this review. Main results We included 20 RCTs involving a total of 1681 individual participants and 1172 individual legs (2853 analytic units). Of these 20 trials, 10 included patients undergoing general surgery; six included patients undergoing orthopaedic surgery; three individual trials included patients undergoing neurosurgery, cardiac surgery, and gynaecological surgery, respectively; and only one trial included medical patients. Graduated compression stockings were applied on the day before surgery or on the day of surgery and were worn up until discharge or until the participants were fully mobile. In the majority of the included studies DVT was identified by the radioactive I 125 uptake test. Duration of follow‐up ranged from seven to 14 days. The included studies were at an overall low risk of bias. We were able to pool the data from 20 studies reporting the incidence of DVT. In the GCS group, 134 of 1445 units developed DVT (9%) in comparison to the control group (without GCS), in which 290 of 1408 units developed DVT (21%). The Peto odds ratio (OR) was 0.35 (95% confidence interval (CI) 0.28 to 0.43; 20 studies; 2853 units; high‐quality evidence), showing an overall effect favouring treatment with GCS (P < 0.001). Based on results from eight included studies, the incidence of proximal DVT was 7 of 517 (1%) units in the GCS group and 28 of 518 (5%) units in the control group. The Peto OR was 0.26 (95% CI 0.13 to 0.53; 8 studies; 1035 units; moderate‐quality evidence) with an overall effect favouring treatment with GCS (P < 0.001). Combining results from five studies, all based on surgical patients, the incidence of PE was 5 of 283 (2%) participants in the GCS group and 14 of 286 (5%) in the control group. The Peto OR was 0.38 (95% CI 0.15 to 0.96; 5 studies; 569 participants; low‐quality evidence) with an overall effect favouring treatment with GCS (P = 0.04). We downgraded the quality of the evidence for proximal DVT and PE due to low event rate (imprecision) and lack of routine screening for PE (inconsistency). We carried out subgroup analysis by speciality (surgical or medical patients . Combining results from 19 trials focusing on surgical patients, 134 of 1365 (9.8%) units developed DVT in the GCS group compared to 282 of 1328 (21.2%) units in the control group. The Peto OR was 0.35 (95% CI 0.28 to 0.44; high‐quality evidence), with an overall effect favouring treatment with GCS (P < 0.001). Based on results from seven included studies, the incidence of proximal DVT was 7 of 437 units (1.6%) in the GCS group and 28 of 438 (6.4%) in the control group. The Peto OR was 0.26 (95% CI 0.13 to 0.53; 875 units; moderate‐quality evidence) with an overall effect favouring treatment with GCS (P < 0.001). We downgraded the evidence for proximal DVT due to low event rate (imprecision). Based on the results from one trial focusing on medical patients admitted following acute myocardial infarction, 0 of 80 (0%) legs developed DVT in the GCS group and 8 of 80 (10%) legs developed DVT in the control group. The Peto OR was 0.12 (95% CI 0.03 to 0.51; low‐quality evidence) with an overall effect favouring treatment with GCS (P = 0.004). None of the medical patients in either group developed a proximal DVT, and the incidence of PE was not reported. Limited data were available to accurately assess the incidence of adverse effects and complications with the use of GCS as these were not routinely quantitatively reported in the included studies. Authors' conclusions There is high‐quality evidence that GCS are effective in reducing the risk of DVT in hospitalised patients who have undergone general and orthopaedic surgery, with or without other methods of background thromboprophylaxis, where clinically appropriate. There is moderate‐quality evidence that GCS probably reduce the risk of proximal DVT, and low‐quality evidence that GCS may reduce the risk of PE. However, there remains a paucity of evidence to assess the effectiveness of GCS in diminishing the risk of DVT in medical patients. Plain language summary Graduated compression stockings for prevention of deep vein thrombosis during a hospital stay Background Deep vein thrombosis (DVT) is a blood clot that forms in a vein deep in the body, usually in the leg or pelvic veins. A number of factors such as reduced mobility, older age, obesity, active cancer, major surgery, major injuries, history of previous DVT, family history of DVT, and recent period of illness may increase the risk of developing a DVT. Hospital patients, who often have one or more of these risk factors, are at particular risk of developing DVT, either immediately after surgery or if they are immobile due to a medical illness. Symptoms of DVT vary from none to pain and swelling in the legs. A blood clot can move from the leg to the lungs, with the danger of pulmonary embolism (PE) and death. The main treatment for DVT includes the use of blood‐thinning drugs (anticoagulation). Deep vein thrombosis usually resolves, but it can have long‐term effects such as high venous pressure in the leg, leg pain, swelling, darkening of the skin, and inflammation. Deep vein thrombosis can be prevented with the use of compression or drugs. Drugs can cause bleeding, which is a particular concern in surgical patients. Graduated compression stockings (GCS) help prevent the formation of blood clots in the legs by applying varying amounts of pressure to different parts of the leg. Study characteristics and key results We identified 20 randomised controlled trials (studies in which participants are assigned to a treatment group using a random method) (2853 analytic units consisting of 1681 individual patients and 1172 individual legs) in our most recent search on 12 June 2018. Nine trials compared wearing stockings to no stockings, and 11 compared stockings plus another method with that method alone. The other methods used were dextran 70, aspirin, heparin, and mechanical sequential compression. Of the 20 trials, 10 included patients undergoing general surgery; six included patients undergoing orthopaedic surgery; three individual trials included patients undergoing neurosurgery, cardiac surgery, and gynaecologi al surgery, respectively; and only one trial included medical patients (patients who were admitted to the hospital for reasons other than surgery). The compression stockings were applied on the day before surgery or on the day of surgery and were worn up until discharge or until the patients were fully mobile. Thigh‐length stockings were used in the vast majority of included studies. The included studies were of good quality overall. We found that wearing GCS reduced the overall risk of developing DVT, and probably also DVT in the thighs. We found that GCS may also reduce the risk of PE amongst patients undergoing surgery. As only one trial included medical patients, results for this population are limited. The occurrence of problems associated with wearing GCS was poorly reported in the included studies. Quality of the evidence Our review confirmed that GCS are effective in reducing the risk of DVT in hospitalised surgical patients (high‐quality evidence). It also demonstrated that GCS probably reduce the risk of developing DVT in the thighs (proximal DVT, moderate‐quality evidence) and PE (low‐quality evidence). Reasons for downgrading the quality of the evidence included low event rate (i.e. small number of participants who developed DVT) and uncertainty due to only a small number of patients being routinely screened for proximal DVT or PE. Limited evidence was available for hospitalised medical patients, with only one study suggesting that GCS may prevent DVT in such patients.