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Dive into the research topics where Karen Welch is active.

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Cochrane Database of Systematic Reviews | 2016

Inhaled corticosteroids for cystic fibrosis

Ian M Balfour‐Lynn; Karen Welch

BACKGROUNDnReduction of lung inflammation is one of the goals of cystic fibrosis therapy. Inhaled corticosteroids are often used to treat children and adults with cystic fibrosis. The rationale for this is their potential to reduce lung damage arising from inflammation, as well as their effect on symptomatic wheezing. It is important to establish the current level of evidence for the risks and benefits of inhaled corticosteroids, especially in the light of their known adverse effects on growth. This is an update of a previously published review.nnnOBJECTIVESnTo assess the effectiveness of taking regular inhaled corticosteroids, compared to not taking them, in children and adults with cystic fibrosis.nnnSEARCH METHODSnWe searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We requested information from pharmaceutical companies manufacturing inhaled corticosteroids and authors of identified trials.Date of most recent search of the Groups Trials Register: 15 August 2016.nnnSELECTION CRITERIAnRandomised or quasi-randomised trials, published and unpublished, comparing inhaled corticosteroids to placebo or standard treatment in individuals with cystic fibrosis.nnnDATA COLLECTION AND ANALYSISnTwo independent authors assessed methodological quality and risk of bias in trials using established criteria and extracted data using standard pro formas.nnnMAIN RESULTSnThe searches identified 34 citations, of which 26 (representing 13 trials) were eligible for inclusion. These 13 trials reported the use of inhaled corticosteroids in 506 people with cystic fibrosis aged between six and 55 years. One was a withdrawal trial in individuals who were already taking inhaled corticosteroids. Methodological quality and risk of bias were difficult to assess from published information. Many of the risk of bias judgements were unclear due to a lack of available information. Only two trials specified how participants were randomised and less than half of the included trials gave details on how allocation was concealed. Trials were generally judged to have a low risk of bias from blinding, except for two which were open label or did not use a placebo. There were some concerns that a number of trials had not been published in peer-reviewed journals, but the risk of bias from this was unclear. Inclusion criteria varied between trials, as did type and duration of treatment and timing of outcome assessments. Objective measures of airway function were reported in most trials but were often incomplete. Significant benefit has not been conclusively demonstrated. Four trials systematically documented adverse effects and growth was significantly affected in one study using high doses.nnnAUTHORS CONCLUSIONSnEvidence from these trials is insufficient to establish whether inhaled corticosteroids are beneficial in cystic fibrosis, but withdrawal in those already taking them has been shown to be safe. There is some evidence they may cause harm in terms of growth. It has not been established whether long-term use is beneficial in reducing lung inflammation, which should improve survival, but it is unlikely this will be proven conclusively in a randomised controlled trial.


Cochrane Database of Systematic Reviews | 2017

Patient education in the management of coronary heart disease

James Pr Brown; Alexander M. Clark; Hayes Dalal; Karen Welch; Rod S Taylor

BACKGROUNDnCoronary heart disease (CHD) is the single most common cause of death globally. However, with falling CHD mortality rates, an increasing number of people live with CHD and may need support to manage their symptoms and improve prognosis. Cardiac rehabilitation is a complex multifaceted intervention which aims to improve the health outcomes of people with CHD. Cardiac rehabilitation consists of three core modalities: education, exercise training and psychological support. This is an update of a Cochrane systematic review previously published in 2011, which aims to investigate the specific impact of the educational component of cardiac rehabilitation.nnnOBJECTIVESn1. To assess the effects of patient education delivered as part of cardiac rehabilitation, compared with usual care on mortality, morbidity, health-related quality of life (HRQoL) and healthcare costs in patients with CHD.2. To explore the potential study level predictors of the effects of patient education in patients with CHD (e.g. individual versus group intervention, timing with respect to index cardiac event).nnnSEARCH METHODSnWe updated searches from the previous Cochrane review, by searching the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library, Issue 6, 2016), MEDLINE (Ovid), Embase (Ovid), PsycINFO (Ovid) and CINAHL (EBSCO) in June 2016. Three trials registries, previous systematic reviews and reference lists of included studies were also searched. No language restrictions were applied.nnnSELECTION CRITERIAn1. Randomised controlled trials (RCTs) where the primary interventional intent was education delivered as part of cardiac rehabilitation.2. Studies with a minimum of six-months follow-up and published in 1990 or later.3. Adults with a diagnosis of CHD.nnnDATA COLLECTION AND ANALYSISnTwo review authors independently screened all identified references for inclusion based on the above inclusion criteria. One author extracted study characteristics from the included trials and assessed their risk of bias; a second review author checked data. Two independent reviewers extracted outcome data onto a standardised collection form. For dichotomous variables, risk ratios and 95% confidence intervals (CI) were derived for each outcome. Heterogeneity amongst included studies was explored qualitatively and quantitatively. Where appropriate and possible, results from included studies were combined for each outcome to give an overall estimate of treatment effect. Given the degree of clinical heterogeneity seen in participant selection, interventions and comparators across studies, we decided it was appropriate to pool studies using random-effects modelling. We planned to undertake subgroup analysis and stratified meta-analysis, sensitivity analysis and meta-regression to examine potential treatment effect modifiers. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to evaluate the quality of the evidence and the GRADE profiler (GRADEpro GDT) to create summary of findings tables.nnnMAIN RESULTSnThis updated review included a total of 22 trials which randomised 76,864 people with CHD to an education intervention or a no education comparator. Nine new trials (8215 people) were included for this update. We judged most included studies as low risk of bias across most domains. Educational dose ranged from one 40 minute face-to-face session plus a 15 minute follow-up call, to a four-week residential stay with 11 months of follow-up sessions. Control groups received usual medical care, typically consisting of referral to an outpatient cardiologist, primary care physician, or both.We found evidence of no difference in effect of education-based interventions on total mortality (13 studies, 10,075 participants; 189/5187 (3.6%) versus 222/4888 (4.6%); random effects risk ratio (RR) 0.80, 95% CI 0.60 to 1.05; moderate quality evidence). Individual causes of mortality were reported rarely, and we were unable to report separate results for cardiovascular mortality or non-cardiovascular mortality. There was evidence of no difference in effect of education-based interventions on fatal and/or non fatal myocardial infarction (MI) (2 studies, 209 participants; 7/107 (6.5%) versus 12/102 (11.8%); random effects RR 0.63, 95% CI 0.26 to 1.48; very low quality of evidence). However, there was some evidence of a reduction with education in fatal and/or non-fatal cardiovascular events (2 studies, 310 studies; 21/152 (13.8%) versus 61/158 (38.6%); random effects RR 0.36, 95% CI 0.23 to 0.56; low quality evidence). There was evidence of no difference in effect of education on the rate of total revascularisations (3 studies, 456 participants; 5/228 (2.2%) versus 8/228 (3.5%); random effects RR 0.58, 95% CI 0.19 to 1.71; very low quality evidence) or hospitalisations (5 studies, 14,849 participants; 656/10048 (6.5%) versus 381/4801 (7.9%); random effects RR 0.93, 95% CI 0.71 to 1.21; very low quality evidence). There was evidence of no difference between groups for all cause withdrawal (17 studies, 10,972 participants; 525/5632 (9.3%) versus 493/5340 (9.2%); random effects RR 1.04, 95% CI 0.88 to 1.22; low quality evidence). Although some health-related quality of life (HRQoL) domain scores were higher with education, there was no consistent evidence of superiority across all domains.nnnAUTHORS CONCLUSIONSnWe found no reduction in total mortality, in people who received education delivered as part of cardiac rehabilitation, compared to people in control groups (moderate quality evidence). There were no improvements in fatal or non fatal MI, total revascularisations or hospitalisations, with education. There was some evidence of a reduction in fatal and/or non-fatal cardiovascular events with education, but this was based on only two studies. There was also some evidence to suggest that education-based interventions may improve HRQoL. Our findings are supportive of current national and international clinical guidelines that cardiac rehabilitation for people with CHD should be comprehensive and include educational interventions together with exercise and psychological therapy. Further definitive research into education interventions for people with CHD is needed.


Cochrane Database of Systematic Reviews | 2011

Antithrombotic agents for preventing thrombosis after infrainguinal arterial bypass surgery

Alistair J Geraghty; Karen Welch

BACKGROUNDnPeripheral arterial disease (PAD) is frequently treated by either an infrainguinal autologous (using the patients own veins) or synthetic graft bypass. The rate of occlusion of the graft after one year is between 12% and 60%. To prevent occlusion, patients are treated with an antiplatelet or antithrombotic drug, or a combination of both. Little is known about which drug is optimal to prevent infrainguinal graft occlusion. This is an update of a Cochrane review first published in 2003.nnnOBJECTIVESnTo evaluate whether antithrombotic treatment improves graft patency, limb salvage and survival in patients with chronic PAD undergoing infrainguinal bypass surgery.nnnSEARCH STRATEGYnThe Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched August 2010) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 3).nnnSELECTION CRITERIAnRandomised, controlled trials; two review authors independently assessed the methodological quality of each trial using a standardised checklist.nnnDATA COLLECTION AND ANALYSISnData collected included patient details, inclusion and exclusion criteria, type of graft, antithrombotic therapy, outcomes, and side effects.nnnMAIN RESULTSnA total of 14 trials were included in this review; 4970 patient results were analysed. Four trials evaluating vitamin K antagonists (VKA) versus no VKA suggested that oral anticoagulation may favour autologous venous, but not artificial, graft patency as well as limb salvage and survival. Two other studies comparing VKA with aspirin (ASA) or aspirin and dipyridamole provided evidence to support a positive effect of VKA on the patency of venous but not artificial grafts. Three trials comparing low molecular weight heparin (LMWH) to unfractionated heparin (UFH) failed to demonstrate a significant difference on patency. One trial comparing LMWH with placebo found no significant improvement in graft patency over the first postoperative year in a population receiving aspirin. One trial showed an advantage for LMWH versus aspirin and dipyridamol at one year for patients undergoing limb salvage procedures. Perioperative administration of ancrod showed no greater benefit when compared to unfractionated heparin. Dextran 70 showed similar graft patency rates to LMWH but a significantly higher proportion of patients developed heart failure with dextran.nnnAUTHORS CONCLUSIONSnPatients undergoing infrainguinal venous graft are more likely to benefit from treatment with VKA than platelet inhibitors. Patients receiving an artificial graft benefit from platelet inhibitors (aspirin). However, the evidence is not conclusive. Randomised controlled trials with larger patient numbers are needed in the future to compare antithrombotic therapies with either placebo or antiplatelet therapies.


European Journal of Preventive Cardiology | 2013

Effect of patient education in the management of coronary heart disease: a systematic review and meta-analysis of randomized controlled trials:

James Pr Brown; Alexander M. Clark; Hasnain M Dalal; Karen Welch; Rod S Taylor

Background: To assess the effects of patient education on mortality, morbidity, health-related quality of life (HRQoL), and healthcare costs in people with coronary heart disease (CHD). Design: Systematic review and meta-analysis. Methods: Data sources were Cochrane Library, Medline, Embase, PsycINFO, CINAHL, and ongoing trial registries until August 2010. We also checked study references. The study selection was based on design (randomized controlled trials with follow up of at least 6 months, published from 1990 onwards), population (adults with CHD), intervention (patient education stated to be the primary intervention), and comparators (usual care or no educational intervention). Results: Thirteen studies (68,556 people with CHD) were included. Educational interventions ranged from two visits to a 4-week residential stay with 11 months of reinforcement sessions. Compared to no educational intervention, there was weak evidence that education reduced all-cause mortality (pooled relative risk (RR) 0.79, 95% CI 0.55 to 1.13) and cardiac morbidity outcomes: myocardial infarction (pooled RR 0.63, 95% CI 0.26 to 1.48), revascularization (pooled RR 0.58, 95% CI 0.19 to 1.71), and hospitalization (pooled RR 0.83, 95% CI 0.65 to 1.07) at median 18-months follow up. There was evidence to suggest that education can improve HRQoL and decrease healthcare costs by reductions in downstream healthcare utilization. Conclusions: Our review had insufficient power to exclude clinically important effects of education on mortality and morbidity. Nevertheless it supports the practice of CHD secondary prevention and rehabilitation programmes including education as an intervention. Further research is needed to determine the most effective and cost-effective format, duration, timing, and methods of education delivery.


Cochrane Database of Systematic Reviews | 2010

Endovascular stents for intermittent claudication.

Paul Bachoo; P A Thorpe; Heather Maxwell; Karen Welch

BACKGROUNDnEndovascular stents have been suggested as a means to improve the patency of arteries after angioplasty in patients with intermittent claudication. This is an update of a Cochrane review published in 2002.nnnOBJECTIVESnThe null hypothesis to be tested by this review is that for individuals with claudication the use of an endovascular stent, in addition to percutaneous transluminal angioplasty, does not improve symptoms of life-style limiting claudication when compared to percutaneous angioplasty alone.nnnSEARCH STRATEGYnFor this update the Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched August 2009) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (last searched 2009, Issue 3).nnnSELECTION CRITERIAnRandomised trials comparing angioplasty alone versus angioplasty with endovascular stents in patients with intermittent claudication.nnnDATA COLLECTION AND ANALYSISnTwo authors independently assessed trial quality and extracted the data. Only published trial data were used but unpublished data were sought for the update. Effectiveness was measured by the pre-defined primary outcome measures restenosis or reocclusion rates and maximum walking distance.nnnMAIN RESULTSnTwo studies were included involving a total of 104 participants. Both studies included only individuals with femoro-popliteal disease. They compared angioplasty and stenting with the Palmaz stent against angioplasty alone. Although one study showed a slight statistical advantage in arterial patency after angioplasty alone, this was not found when the two studies were combined. No differences in the secondary outcomes were detected in either study.nnnAUTHORS CONCLUSIONSnThe small number of relevant studies identified together with the small sample sizes and methodological weaknesses severely limit the usefulness of this review in guiding practice. The results from larger multicentre trials are needed.


Cochrane Database of Systematic Reviews | 2010

Patient education in the contemporary management of coronary heart disease

James Pr Brown; Alexander M. Clark; Hayes Dalal; Karen Welch; Rod S Taylor

This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the effects of patient education compared with usual care on mortality and morbidity in patients with CHD.To explore the potential study level predictors of the effects of patient education in patients with CHD.


Cochrane Database of Systematic Reviews | 2016

D‐dimer test for excluding the diagnosis of pulmonary embolism

Fay Crawford; Alina Andras; Karen Welch; Karen Sheares; David Keeling; Francesca M. Chappell

BACKGROUNDnPulmonary embolism (PE) can occur when a thrombus (blood clot) travels through the veins and lodges in the arteries of the lungs, producing an obstruction. People who are thought to be at risk include those with cancer, people who have had a recent surgical procedure or have experienced long periods of immobilisation and women who are pregnant. The clinical presentation can vary, but unexplained respiratory symptoms such as difficulty breathing, chest pain and an increased respiratory rate are common.D-dimers are fragments of protein released into the circulation when a blood clot breaks down as a result of normal body processes or with use of prescribed fibrinolytic medication. The D-dimer test is a laboratory assay currently used to rule out the presence of high D-dimer plasma levels and, by association, venous thromboembolism (VTE). D-dimer tests are rapid, simple and inexpensive and can prevent the high costs associated with expensive diagnostic tests.nnnOBJECTIVESnTo investigate the ability of the D-dimer test to rule out a diagnosis of acute PE in patients treated in hospital outpatient and accident and emergency (A&E) settings who have had a pre-test probability (PTP) of PE determined according to a clinical prediction rule (CPR), by estimating the accuracy of the test according to estimates of sensitivity and specificity. The review focuses on those patients who are not already established on anticoagulation at the time of study recruitment.nnnSEARCH METHODSnWe searched 13 databases from conception until December 2013. We cross-checked the reference lists of relevant studies.nnnSELECTION CRITERIAnTwo review authors independently applied exclusion criteria to full papers and resolved disagreements by discussion.We included cross-sectional studies of D-dimer in which ventilation/perfusion (V/Q) scintigraphy, computerised tomography pulmonary angiography (CTPA), selective pulmonary angiography and magnetic resonance pulmonary angiography (MRPA) were used as the reference standard.•nnnPARTICIPANTSnAdults who were managed in hospital outpatient and A&E settings and were suspected of acute PE were eligible for inclusion in the review if they had received a pre-test probability score based on a CPR.•nnnINDEX TESTSnquantitative, semi quantitative and qualitative D-dimer tests.• Target condition: acute symptomatic PE.• Reference standards: We included studies that used pulmonary angiography, V/Q scintigraphy, CTPA and MRPA as reference standard tests.nnnDATA COLLECTION AND ANALYSISnTwo review authors independently extracted data and assessed quality using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). We resolved disagreements by discussion. Review authors extracted patient-level data when available to populate 2 × 2 contingency tables (true-positives (TPs), true-negatives (TNs), false-positives (FPs) and false-negatives (FNs)).nnnMAIN RESULTSnWe included four studies in the review (n = 1585 patients). None of the studies were at high risk of bias in any of the QUADAS-2 domains, but some uncertainty surrounded the validity of studies in some domains for which the risk of bias was uncertain. D-dimer assays demonstrated high sensitivity in all four studies, but with high levels of false-positive results, especially among those over the age of 65 years. Estimates of sensitivity ranged from 80% to 100%, and estimates of specificity from 23% to 63%.nnnAUTHORS CONCLUSIONSnA negative D-dimer test is valuable in ruling out PE in patients who present to the A&E setting with a low PTP. Evidence from one study suggests that this test may have less utility in older populations, but no empirical evidence was available to support an increase in the diagnostic threshold of interpretation of D-dimer results for those over the age of 65 years.


Cochrane Database of Systematic Reviews | 2016

Ankle brachial index for the diagnosis of lower limb peripheral arterial disease

Fay Crawford; Karen Welch; Alina Andras; Francesca M. Chappell

BACKGROUNDnPeripheral arterial disease (PAD) of the lower limb is common, with prevalence of both symptomatic and asymptomatic disease estimated at 13% in the over 50 age group. Symptomatic PAD affects about 5% of individuals in Western populations between the ages of 55 and 74 years. The most common initial symptom of PAD is muscle pain on exercise that is relieved by rest and is attributed to reduced lower limb blood flow due to atherosclerotic disease (intermittent claudication). The ankle brachial index (ABI) is widely used by a variety of healthcare professionals, including specialist nurses, physicians, surgeons and podiatrists working in primary and secondary care settings, to assess signs and symptoms of PAD. As the ABI test is non-invasive and inexpensive and is in widespread clinical use, a systematic review of its diagnostic accuracy in people presenting with leg pain suggestive of PAD is highly relevant to routine clinical practice.nnnOBJECTIVESnTo estimate the diagnostic accuracy of the ankle brachial index (ABI) - also known as the ankle brachial pressure index (ABPI) - for the diagnosis of peripheral arterial disease in people who experience leg pain on walking that is alleviated by rest.nnnSEARCH METHODSnWe carried out searches of the following databases in August 2013: MEDLINE (Ovid SP),Embase (Ovid SP), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO), Latin American and Caribbean Health Sciences (LILACS) (Bireme), Database of Abstracts of Reviews of Effects and the Health Technology Assessment Database in The Cochrane Library, the Institute for Scientific Information (ISI) Conference Proceedings Citation Index - Science, the British Library Zetoc Conference search and Medion.nnnSELECTION CRITERIAnWe included cross-sectional studies of ABI in which duplex ultrasonography or angiography was used as the reference standard. We also included cross-sectional or diagnostic test accuracy (DTA) cohort studies consisting of both prospective and retrospective studies.Participants were adults presenting with leg pain on walking that was relieved by rest, who were tested in primary care settings or secondary care settings (hospital outpatients only) and who did not have signs or symptoms of critical limb ischaemia (rest pain, ischaemic ulcers or gangrene).The index test was ABI, also called the ankle brachial pressure index (ABPI) or the Ankle Arm Index (AAI), which was performed with a hand-held doppler or oscillometry device to detect ankle vessels. We included data collected via sphygmomanometers (both manual and aneroid) and digital equipment.nnnDATA COLLECTION AND ANALYSISnTwo review authors independently replicated data extraction by using a standard form, which included an assessment of study quality, and resolved disagreements by discussion. Two review authors extracted participant-level data when available to populate 2×2 contingency tables (true positives, true negatives, false positives and false negatives).After a pilot phase involving two review authors working independently, we used the methodological quality assessment tool the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), which incorporated our review question - along with a flow diagram to aid reviewers understanding of the conduct of the study when necessary and an assessment of risk of bias and applicability judgements.nnnMAIN RESULTSnWe screened 17,055 records identified through searches of databases. We obtained 746 full-text articles and assessed them for relevance. We scrutinised 49 studies to establish their eligibility for inclusion in the review and excluded 48, primarily because participants were not patients presenting solely with exertional leg pain, investigators used no reference standard or investigators used neither angiography nor duplex ultrasonography as the reference standard. We excluded most studies for more than one reason.Only one study met the eligibility criteria and provided limb-level accuracy data from just 85 participants (158 legs). This prospective study compared the manual doppler method of obtaining an ABI (performed by untrained personnel) with the automated oscillometric method. Limb-level data, as reported by the study, indicated that the accuracy of the ABI in detecting significant arterial disease on angiography is superior when stenosis is present in the femoropopliteal vessels, with sensitivity of 97% (95% confidence interval (CI) 93% to 99%) and specificity of 89% (95% CI 67% to 95%) for oscillometric ABI, and sensitivity of 95% (95% CI 89% to 97%) and specificity of 56% (95% CI 33% to 70%) for doppler ABI. The ABI threshold was not reported. Investigators attributed the lower specificity for doppler to the fact that a tibial or dorsalis pedis pulse could not be detected by doppler in 12 of 27 legs with normal vessels or non-significant lesions. The superiority of the oscillometric (automated) method for obtaining an ABI reading over the manual method with a doppler probe used by inexperienced operators may be a clinically important finding.nnnAUTHORS CONCLUSIONSnEvidence about the accuracy of the ankle brachial index for the diagnosis of PAD in people with leg pain on exercise that is alleviated by rest is sparse. The single study included in our review provided only limb-level data from a few participants. Well-designed cross-sectional studies are required to evaluate the accuracy of ABI in patients presenting with early symptoms of peripheral arterial disease in all healthcare settings. Another systematic review of existing studies assessing the use of ABI in alternative patient groups, including asymptomatic, high-risk patients, is required.


Cochrane Database of Systematic Reviews | 2014

Duplex ultrasound for the diagnosis of symptomatic deep vein thrombosis in the lower limb

Francesca M. Chappell; Fay Crawford; Alina Andras; Steve Goodacre; James McCaslin; Karen Welch; Crispian Oates

This is the protocol for a review and there is no abstract. The objectives are as follows: n nTo estimate the sensitivity and specificity of duplex ultrasound for the detection of distal and proximal DVT in symptomatic patients with prior testing by a clinical prediction rule (with or without additional D-dimer testing). n nThe accuracy of ultrasound for DVT may be affected by body mass index and whether the patient has had a previous DVT. If possible, we shall investigate both previous DVT and body mass index as possible sources of heterogeneity, but recognise that these are patient-specific rather than study-specific characteristics. This means that results reported at the study level, for example average body mass index, may not be informative in an analysis and are more appropriately investigated with individual patient data. However, such an analysis may be possible if studies report results stratified by previous DVT status or body mass index. Two study-specific characteristics we shall investigate are the generation of the technology of the ultrasound scanner and type of reference standard: ascending venography, CT venography, or MR venography. Moreover, as the accuracy of duplex ultrasound depends on whether the DVT is distal or proximal, we shall perform separate meta-analyses according to site.


Cochrane Database of Systematic Reviews | 2016

D‐Dimer tests for the diagnosis of deep venous thrombosis in symptomatic hospital outpatients with a clinical prediction rule

Francesca M. Chappell; Alina Andras; Karen Welch; Marcello Di Nisio; Lindsay Robertson; Marlene Stewart; Fay Crawford

This is the protocol for a review and there is no abstract. The objectives are as follows: n nTo estimate the sensitivity and specificity of the various types of D-dimer test in the diagnosis of deep vein thrombosis (DVT) of the lower limb in symptomatic outpatients with a clinical prediction rule score. Patients clinical prediction rule scores will be used to assess D-dimer test accuracy in different risk groups. n nTo investigate the following as potential sources of heterogeneity: age, sex, cancer, previous venous thromboembolism (VTE), prolonged immobilisation, anticoagulant treatment, time lapse between onset of symptoms and testing, and type of reference standard. However, we recognise that all of these listed items, except type of reference standard, are patient-specific rather than study-specific, and so study reports may lack the necessary level of detail to enable an informative analysis.

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Fay Crawford

Queen Margaret Hospital

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