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.
Overall summary High risk of bias in the review
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|
|Number of studies||20|
|Number of participants||1681|
|Last search date||12th June 2018|
|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|
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.
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|