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Thomas E Locker

Bio: Thomas E Locker is an academic researcher from University of Sheffield. The author has contributed to research in topics: Emergency department & Public health surveillance. The author has an hindex of 18, co-authored 27 publications receiving 1472 citations. Previous affiliations of Thomas E Locker include Barnsley Hospital NHS Foundation Trust & College of Emergency Medicine.

Papers
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Journal ArticleDOI
31 Jan 2004-BMJ
TL;DR: Care in a chest pain observation unit seems to be more effective and more cost effective than routine care for patients with acute, undifferentiated chest pain.
Abstract: Objectives To measure the effectiveness and cost effectiveness of providing care in a chest pain observation unit compared with routine care for patients with acute, undifferentiated chest pain. Design Cluster randomised controlled trial, with 442 days randomised to the chest pain observation unit or routine care, and cost effectiveness analysis from a health service costing

254 citations

Journal ArticleDOI
TL;DR: It is identified that there is a group of patients who present repeatedly due to non-random events, confirming the existence of “frequent users” in the ED.
Abstract: Objective: This study aimed to develop a definition of frequent use of an emergency department (ED) by comparing differences in the observed frequency distribution with that of a theoretical frequency distribution. Methods: A retrospective analysis of attendance of ED and minor injury unit attendances in one city over 1 year was conducted. From these data, the expected frequency distribution was determined based upon a Poisson distribution. Results: During the period studied, 75 141 people attended on 98 908 occasions. The theoretical frequency distribution showed that there were 2764 (3.7%) “frequent users” presenting repeatedly due to non-random events. These patients made 12 316 (12.4%) attendances. Frequent users were older than chance users (mean age 49.7 vs 44.5 years). A greater proportion arrived by ambulance (55.3% vs 27.5%), presented with psychiatric problems (5.8% vs 1.1%) or alcohol intoxication (1.3% vs 0.5%), and were admitted to hospital (37.4% vs 19.6%). Conclusion: We have identified that there is a group of patients who present repeatedly due to non-random events, confirming the existence of “frequent users”. Their characteristics are clearly different to other patients in the ED. We propose that “frequent users” be defined as any patient who makes more than four attendances per year.

187 citations

Journal ArticleDOI
TL;DR: To estimate the diagnostic accuracy of non-invasive tests for proximal deep vein thrombosis (DVT) and isolated calf DVT, in patients with clinically suspected DVT or high-risk asymptomatic patients, and identify factors associated with variation in diagnostic performance.
Abstract: Objectives: To estimate the diagnostic accuracy of non-invasive tests for proximal deep vein thrombosis (DVT) and isolated calf DVT, in patients with clinically suspected DVT or high-risk asymptomatic patients, and identify factors associated with variation in diagnostic performance. Also to identify practical diagnostic algorithms for DVT, and estimate the diagnostic accuracy, clinical effectiveness and cost-effectiveness of each. Data sources: Electronic databases (to April 2004). A postal survey of hospitals in the UK. Review methods: Selected studies were assessed against validated criteria. A postal survey of hospitals in the UK was undertaken to describe current practice and availability of tests, and identify additional diagnostic algorithms. Pooled estimates of sensitivity, specificity and likelihood ratios were obtained for each test using random effects meta-analysis. The effect of study-level covariates was explored using random effects metaregression. A decision-analytic model was used to combine estimates from the meta-analysis and estimate the diagnostic performance of each algorithm in a theoretical population of outpatients with suspected DVT. The net benefit of using each algorithm was estimated from a health service perspective, using cost–utility analysis, assuming thresholds of willingness to pay of £20,000 and £30,000 per quality-adjusted lifeyear (QALY). The model was analysed probabilistically and cost-effectiveness acceptability curves were generated to reflect uncertainty in estimated costeffectiveness. Results: Individual clinical features are of limited diagnostic value, with most likelihood ratios being close to 1. Wells clinical probability score stratifies proximal, but not distal, DVT into high-, intermediate- and low-risk categories. Unstructured clinical assessment by experienced clinicians may have similar performance to Wells score. In patients with clinically suspected DVT, D-dimer has 91% sensitivity and 55% specificity for DVT, although performance varies substantially between assays and populations. D-dimer specificity is dependent on pretest clinical probability, being higher in patients with a low clinical probability of DVT. Plethysmography and rheography techniques have modest sensitivity for proximal DVT, poor sensitivity for distal DVT, and modest specificity. Ultrasound has 94% sensitivity for proximal DVT, 64% sensitivity for distal DVT and 94% specificity. Computed tomography scanning has 95% sensitivity for all DVT (proximal and distal combined) and 97% specificity. Magnetic resonance imaging has 92% sensitivity for all DVT and 95% specificity. The diagnostic performance of all tests is worse in asymptomatic patients. The most costeffective algorithm discharged patients with a low Wells score and negative D-dimer without further testing, and then used plethysmography alongside ultrasound, with venography in selected cases, to diagnose the remaining patients. However, the cost-effectiveness of this algorithm was dependent on assumptions of test independence being met and the ability to provide plethysmography at relatively low cost. Availability of plethysmography and venography is currently limited at most UK hospitals, so implementation would involve considerable reorganisation of services. Two algorithms were identified that offered high net benefit and would be feasible in most hospitals without substantial reorganisation of services. Both involved using a combination of Wells score, D-dimer and above-knee ultrasound. For thresholds of willingness to pay of £10,000 or £20,000 per QALY the optimal strategy involved discharging patients with a low or intermediate Wells score and negative D-dimer, ultrasound for those with a high score or positive D-dimer, and repeat scanning for those with positive D-dimer and a high Wells score, but negative initial scan. For thresholds of £30,000 or more a similar strategy, but involving repeat ultrasound for all those with a negative initial scan, was optimal. Conclusions: Diagnostic algorithms based on a combination of Wells score, D-dimer and ultrasound (with repeat if negative) are feasible at most UK hospitals and are among the most cost-effective. Use of repeat scanning depends on the threshold for willingness to pay for health gain. Further diagnostic testing for patients with a low Wells score and negative D-dimer is unlikely to represent a cost-effective use of resources. Recommendations for research include the evaluation of the costs and outcomes of using the optimal diagnostic algorithms in routine practice, the development and evaluation of algorithms appropriate for specific groups of patients with suspected DVT, such as intravenous drug abusers, pregnant patients and those with previous DVT, the evaluation of the role of plethysmography: interaction with other diagnostic tests, outcome of low-risk patients with negative plethysmography and measurement of the costs of providing plethysmography, and methodological research into the incorporation of meta-analytic data into decision-analytic modelling.

183 citations

Journal ArticleDOI
TL;DR: Important differences exist when clinical features are specifically investigated in patients with acute chest pain and a nondiagnostic electrocardiogram.
Abstract: Objectives: To measure the predictive value and diagnostic performance of clinical features used to diagnose coronary syndromes in patients presenting with acute, undifferentiated chest pain. Methods: The clinical features of patients presenting to the authors' chest pain unit with acute, undifferentiated chest pain were prospectively recorded on a standard form. Admitted patients were followed up by case note review. Discharged patients were followed up as outpatients three days later. Six months after the emergency department visit, evidence of adverse events was searched for from the hospital computer database, case notes, and the patient's primary care physician. The authors tested the power of each feature to predict: 1) acute myocardial infarction (AMI) by World Health Organization criteria, and 2) any acute coronary syndrome (ACS), evidenced by cardiac testing, AMI, arrhythmia, death, or revacsularization procedure within six months. Results: Eight hundred ninety-three patients were assessed, 34 (3.8%) with AMI and 81 (9.1%) with ACS. Features useful in the diagnosis of AMI were exertional pain [likelihood ratio (LR) = 2.35], pain radiating to the shoulder or both arms (LR = 4.07), and chest wall tenderness (LR = 0.3). Features useful in the diagnosis of ACS were exertional pain (LR = 2.06) and pain radiating to the shoulder, the left arm, or both arms (LR = 1.62). The site or nature of pain and the presence of nausea, vomiting, or diaphoresis were not predictive of AMI or ACS. Conclusions: Important differences exist when clinical features are specifically investigated in patients with acute chest pain and a nondiagnostic electrocardiogram. Clinical features have a limited role to play in triage decision making.

143 citations

Journal ArticleDOI
TL;DR: The introduction of a time target reduced the proportion of patients staying greater than 4 hours and more patients departed within 20 minutes of the target 4-hour interval after the mandate, notably, the elderly.

133 citations


Cited by
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01 Jan 2009
TL;DR: Physicians should consider modification of immunosuppressive regimens to decrease the risk of PTD in high-risk transplant recipients and Randomized trials are needed to evaluate the use of oral glucose-lowering agents in transplant recipients.
Abstract: OBJECTIVE — To systematically review the incidence of posttransplantation diabetes (PTD), risk factors for its development, prognostic implications, and optimal management. RESEARCH DESIGN AND METHODS — We searched databases (MEDLINE, EMBASE, the Cochrane Library, and others) from inception to September 2000, reviewed bibliographies in reports retrieved, contacted transplantation experts, and reviewed specialty journals. Two reviewers independently determined report inclusion (original studies, in all languages, of PTD in adults with no history of diabetes before transplantation), assessed study methods, and extracted data using a standardized form. Meta-regression was used to explain between-study differences in incidence. RESULTS — Nineteen studies with 3,611 patients were included. The 12-month cumulative incidence of PTD is lower (10% in most studies) than it was 3 decades ago. The type of immunosuppression explained 74% of the variability in incidence (P 0.0004). Risk factors were patient age, nonwhite ethnicity, glucocorticoid treatment for rejection, and immunosuppression with high-dose cyclosporine and tacrolimus. PTD was associated with decreased graft and patient survival in earlier studies; later studies showed improved outcomes. Randomized trials of treatment regimens have not been conducted. CONCLUSIONS — Physicians should consider modification of immunosuppressive regimens to decrease the risk of PTD in high-risk transplant recipients. Randomized trials are needed to evaluate the use of oral glucose-lowering agents in transplant recipients, paying particular attention to interactions with immunosuppressive drugs. Diabetes Care 25:583–592, 2002

3,716 citations

Journal ArticleDOI
TL;DR: In contrast to adults, cardiac arrest in infants and children does not usually result from a primary cardiac cause, more often it is the terminal result of progressive respiratory failure or shock, also called an asphyxial arrest.
Abstract: In contrast to adults, cardiac arrest in infants and children does not usually result from a primary cardiac cause. More often it is the terminal result of progressive respiratory failure or shock, also called an asphyxial arrest. Asphyxia begins with a variable period of systemic hypoxemia, hypercapnea, and acidosis, progresses to bradycardia and hypotension, and culminates with cardiac arrest.1 Another mechanism of cardiac arrest, ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT), is the initial cardiac rhythm in approximately 5% to 15% of pediatric in-hospital and out-of-hospital cardiac arrests;2,–,9 it is reported in up to 27% of pediatric in-hospital arrests at some point during the resuscitation.6 The incidence of VF/pulseless VT cardiac arrest rises with age.2,4 Increasing evidence suggests that sudden unexpected death in young people can be associated with genetic abnormalities in myocyte ion channels resulting in abnormalities in ion flow (see “Sudden Unexplained Deaths,” below). Since 2010 marks the 50th anniversary of the introduction of cardiopulmonary resuscitation (CPR),10 it seems appropriate to review the progressive improvement in outcome of pediatric resuscitation from cardiac arrest. Survival from in-hospital cardiac arrest in infants and children in the 1980s was around 9%.11,12 Approximately 20 years later, that figure had increased to 17%,13,14 and by 2006, to 27%.15,–,17 In contrast to those favorable results from in-hospital cardiac arrest, overall survival to discharge from out-of-hospital cardiac arrest in infants and children has not changed substantially in 20 years and remains at about 6% (3% for infants and 9% for children and adolescents).7,9 It is unclear why the improvement in outcome from in-hospital cardiac arrest has occurred, although earlier recognition and management of at-risk patients on general inpatient units …

1,846 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a two-dimensional magnetic resonance imaging (2D) and three-dimensional (3D) image of the human femoral artery for the diagnosis of acute coronary syndrome.
Abstract: 2D : two-dimensional 3D : three-dimensional ABI : ankle–brachial index ACAS : Asymptomatic Carotid Atherosclerosis Study ACCF : American College of Cardiology Foundation ACE : angiotensin-converting enzyme ACS : acute coronary syndrome ACST : Asymptomatic Carotid Surgery Trial ALI : acute limb ischaemia ASTRAL : Angioplasty and Stenting for Renal Artery Lesions trial BASIL : Bypass versus Angioplasty in Severe Ischaemia of the Leg BOA : Dutch Bypass Oral Anticoagulants or Aspirin CABG : coronary artery bypass grafting CAD : coronary artery disease CAPRIE : Clopidogrel versus Aspirin in Patients at Risk for Ischaemic Events CAPTURE : Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events CARP : Coronary Artery Revascularization Prophylaxis CAS : carotid artery stenting CASPAR : Clopidogrel and Acetylsalicylic Acid in Bypass Surgery for Peripheral Arterial Disease CASS : Coronary Artery Surgery Study CAVATAS : CArotid and Vertebral Artery Transluminal Angioplasty Study CEA : carotid endarterectomy CHARISMA : Clopidogrel for High Atherothrombotic Risk and Ischaemic Stabilization, Management and Avoidance CI : confidence interval CLEVER : Claudication: Exercise Versus Endoluminal Revascularization CLI : critical limb ischaemia CORAL : Cardiovascular Outcomes in Renal Atherosclerotic Lesions COURAGE : Clinical Outcomes Utilization Revascularization and Aggressive Drug Evaluation CPG : Committee for Practice Guidelines CREST : Carotid Revascularization Endarterectomy vs. Stenting Trial CT : computed tomography CTA : computed tomography angiography CVD : cardiovascular disease DECREASE-V : Dutch Echocardiographic Cardiac Risk Evaluation DRASTIC : Dutch Renal Artery Stenosis Intervention Cooperative Study DSA : digital subtraction angiography DUS : duplex ultrasound/duplex ultrasonography EACTS : European Association for Cardio-Thoracic Surgery EAS : European Atherosclerosis Society ECST : European Carotid Surgery Trial EPD : embolic protection device ESC : European Society of Cardiology ESH : European Society of Hypertension ESRD : end-stage renal disease EUROSCORE : European System for Cardiac Operative Risk Evaluation EVA-3S : Endarterectomy Versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis EXACT : Emboshield and Xact Post Approval Carotid Stent Trial GALA : General Anaesthesia versus Local Anaesthesia for Carotid Surgery GFR : glomerular filtration rate GRACE : Global Registry of Acute Coronary Events HbA1c : glycated haemoglobin HDL : high-density lipoprotein HOPE : Heart Outcomes Prevention Evaluation HR : hazard ratio IC : intermittent claudication ICSS : International Carotid Stenting Study IMT : intima–media thickness ITT : intention to treat LDL : low-density lipoprotein LEAD : lower extremity artery disease MACCEs : major adverse cardiac and cerebrovascular events MDCT : multidetector computed tomography MONICA : Monitoring of Trends and Determinants in Cardiovascular Disease MRA : magnetic resonance angiography MRI : magnetic resonance imaging NASCET : North American Symptomatic Carotid Endarterectomy Trial ONTARGET : Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial OR : odds ratio PAD : peripheral artery diseases PARTNERS : Peripheral Arterial Disease Awareness, Risk, and Treatment: New Resources for Survival PCI : percutaneous coronary intervention PET : positron emission tomography PRO-CAS : Predictors of Death and Stroke in CAS PTA : percutaneous transluminal angioplasty RAAS : renin–angiotensin–aldosterone system RADAR : Randomized, Multicentre, Prospective Study Comparing Best Medical Treatment Versus Best Medical Treatment Plus Renal Artery Stenting in Patients With Haemodynamically Relevant Atherosclerotic Renal Artery Stenosis RAS : renal artery stenosis RCT : randomized controlled trial REACH : Reduction of Atherothrombosis for Continued Health RR : risk ratio SAPPHIRE : Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy SCAI : Society for Cardiovascular Angiography and Interventions SIR : Society of Interventional Radiology SPACE : Stent-Protected Angioplasty versus Carotid Endarterectomy SPARCL : Stroke Prevention by Aggressive Reduction in Cholesterol Levels Study STAR : Stent Placement in Patients With Atherosclerotic Renal Artery Stenosis and Impaired Renal Function SSYLVIA : Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial Arteries SVMB : Society for Vascular Medicine and Biology TASC : TransAtlantic Inter-Society Consensus TIA : transient ischaemic attack UEAD : upper extremity artery disease VA : vertebral artery Guidelines summarize and evaluate all available evidence, at the time of the writing process, on a particular issue with the aim of assisting physicians in selecting the best management strategies for an individual patient, with a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines are no substitutes but are complements for textbooks and cover the ESC Core Curriculum topics. Guidelines and recommendations should help the physicians to make decisions in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible physician(s). A large number of Guidelines have been issued in recent years by the European Society of Cardiology (ESC) as well as by other societies and organizations. Because of the impact on clinical practice, quality criteria for the development of guidelines have been established in order to make all decisions transparent to the user. The recommendations for formulating and issuing ESC Guidelines can be found on the ESC website (http://www.escardio.org/guidelines-surveys/esc-guidelines/about/Pages/rules-writing.aspx). ESC Guidelines represent the official position of the ESC on a given topic and are regularly updated. Members of this Task Force were selected by the ESC to represent professionals involved with the medical care of patients with this pathology. Selected experts in the field undertook a comprehensive review of the published evidence for diagnosis, management, and/or prevention of a given condition according to ESC Committee for Practice Guidelines (CPG) policy. A critical evaluation of diagnostic and therapeutic procedures was performed including assessment of the risk–benefit ratio. Estimates of expected health outcomes for larger populations were included, where data exist. The level of evidence and the strength of recommendation of particular treatment options were weighed and graded according to pre-defined scales, as outlined in Tables 1 and 2 . …

1,266 citations

Journal ArticleDOI
TL;DR: In this article, the authors examine the robustness of the regime of targets and terror to these assumptions using evidence from the English public health service on reported successes, problems of measurement, and gaming.
Abstract: In the 2000s, governments in the UK, particularly in England, developed a system of governance of public services that combined targets with an element of terror This has obvious parallels with the Soviet regime, which was initially successful but then collapsed Assumptions underlying governance by targets represent synecdoche (taking a part to stand for a whole); and that problems of measurement and gaming do not matter We examine the robustness of the regime of targets and terror to these assumptions using evidence from the English public health service on reported successes, problems of measurement, and gaming Given this account, we consider the adequacy of current audit arrangements and ways of developing governance by targets in order to counter the problems we have identified

1,210 citations

Journal ArticleDOI
TL;DR: There was convincing evidence that outcome reporting bias exists and has an impact on the pooled summary in systematic reviews, and empirical evidence suggests that published studies tended to report a greater treatment effect than those from the grey literature.
Abstract: Objectives To identify and appraise empirical studies on publication and related biases published since 1998; to assess methods to deal with publication and related biases; and to examine, in a random sample of published systematic reviews, measures taken to prevent, reduce and detect dissemination bias. Data sources The main literature search, in August 2008, covered the Cochrane Methodology Register Database, MEDLINE, EMBASE, AMED and CINAHL. In May 2009, PubMed, PsycINFO and OpenSIGLE were also searched. Reference lists of retrieved studies were also examined. Review methods In Part I, studies were classified as evidence or method studies and data were extracted according to types of dissemination bias or methods for dealing with it. Evidence from empirical studies was summarised narratively. In Part II, 300 systematic reviews were randomly selected from MEDLINE and the methods used to deal with publication and related biases were assessed. Results Studies with significant or positive results were more likely to be published than those with non-significant or negative results, thereby confirming findings from a previous HTA report. There was convincing evidence that outcome reporting bias exists and has an impact on the pooled summary in systematic reviews. Studies with significant results tended to be published earlier than studies with non-significant results, and empirical evidence suggests that published studies tended to report a greater treatment effect than those from the grey literature. Exclusion of non-English-language studies appeared to result in a high risk of bias in some areas of research such as complementary and alternative medicine. In a few cases, publication and related biases had a potentially detrimental impact on patients or resource use. Publication bias can be prevented before a literature review (e.g. by prospective registration of trials), or detected during a literature review (e.g. by locating unpublished studies, funnel plot and related tests, sensitivity analysis modelling), or its impact can be minimised after a literature review (e.g. by confirmatory large-scale trials, updating the systematic review). The interpretation of funnel plot and related statistical tests, often used to assess publication bias, was often too simplistic and likely misleading. More sophisticated modelling methods have not been widely used. Compared with systematic reviews published in 1996, recent reviews of health-care interventions were more likely to locate and include non-English-language studies and grey literature or unpublished studies, and to test for publication bias. Conclusions Dissemination of research findings is likely to be a biased process, although the actual impact of such bias depends on specific circumstances. The prospective registration of clinical trials and the endorsement of reporting guidelines may reduce research dissemination bias in clinical research. In systematic reviews, measures can be taken to minimise the impact of dissemination bias by systematically searching for and including relevant studies that are difficult to access. Statistical methods can be useful for sensitivity analyses. Further research is needed to develop methods for qualitatively assessing the risk of publication bias in systematic reviews, and to evaluate the effect of prospective registration of studies, open access policy and improved publication guidelines.

844 citations