Changes

September 2023 — reviewed. A literature search was conducted in August 2023 to identify evidence-based guidelines, UK policy, systematic reviews, and key randomized controlled trials published since the last revision of the topic. No changes have been made to the recommendations.

Update

Goals

To support primary healthcare professionals to:

• Detect people with possible pulmonary embolism (PE) and manage them appropriately.
• Follow up people with confirmed PE to ensure that they are receiving appropriate monitoring of anticoagulation treatment, appropriate cancer screening, thrombophilia screening (if necessary), and appropriate management during pregnancy.

Outcome measures

Audit criteria

QOF indicators

QIPP - Options for local implementation

NICE quality standards

Venous thromboembolism in adults

• People aged 16 and over who are in hospital and assessed as needing pharmacological venous thromboembolism (VTE) prophylaxis start it as soon as possible and within 14 hours of hospital admission. 
• People aged 16 and over who are discharged with lower limb immobilisation are assessed to identify their risk of VTE. 
• People aged 18 and over with a deep vein thrombosis (DVT) Wells' score of 2 points or more have a proximal leg vein ultrasound scan within 4 hours of it being requested. 
• People aged 18 and over taking anticoagulation treatment after a VTE have a review at 3 months and then at least once a year if they continue to take it long-term.
• People aged 18 and over having outpatient treatment for suspected or confirmed low-risk pulmonary embolism (PE) have an agreed plan for monitoring and follow-up.

[NICE, 2021]

What is it?

• Deep vein thrombosis (DVT) is the term used to describe the formation of a thrombus (blood clot) in a deep vein. The deep veins of the lower limbs are most commonly affected, but thrombosis may affect other sites, including the upper limbs, cerebral veins, and splanchnic veins. For more information, see the CKS topic on Deep vein thrombosis.
• Pulmonary embolism (PE) is a life-threatening condition in which one or more emboli, usually arising from a thrombus formed in the veins, are lodged in and obstruct the pulmonary arterial system, causing severe respiratory dysfunction.
  • Provoked PE is associated with a recent (within 3 months) and transient major risk factor, such as significant immobility, surgery, trauma, pregnancy or puerperium, or use of hormonal therapy (combined contraceptive pill or hormone replacement therapy). 
  • Unprovoked PE occurs in the absence of a recent (within 3 months) major clinical risk factor in a person who is not using hormonal therapy. 
  • Note: the European Society of Cardiology no longer supports the use of the terms 'provoked' and 'unprovoked' as they are potentially misleading and are not helpful when making a decision about the duration of anticoagulation treatment.  
• Venous thromboembolism is a term used to encompass both PE and DVT. 

 [SIGN, 2014; Konstantinides, 2020; BMJ Best Practice, 2022; NICE, 2023]

How common is it?

• Venous thromboembolism (VTE), encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third most common cardiovascular disease (after acute myocardial infarction and stroke), with an overall annual incidence of 53–162 per 100,000 people [Konstantinides, 2020].
• The annual incidence rates of PE in epidemiological studies range from 39 to 115 per 100,000 population [Konstantinides, 2020].
• In the UK, over 69,064 hospital episodes of PE were reported between 2021–2022, resulting in 36,757 admissions [NHS Digital, 2022]. 
• An epidemiological model constructed to assess the number of VTE events and associated morbidity and mortality in Europe estimated that over 295,000 cases of PE occur every year in six European countries (with a total population of 454.4 million) [Cohen, 2007]. 

What are the risk factors?

• About one-third to one-half of venous thromboembolism (VTE) episodes do not have an identifiable risk factor [Di Nisio, 2016]. The remaining episodes are caused by transient or persistent factors that increase the risk of VTE by inducing hypercoagulability, venous stasis, or vascular wall damage or dysfunction (known collectively as Virchow’s triad).
• Strong risk factors for pulmonary embolism (PE) include:
  • Deep vein thrombosis (DVT) — about 45-50% of people with PE have concomitant DVT.
  • Recent surgery — surgery within the last 2 months is present in 29% of people with confirmed PE.
    • The risk of VTE is especially high for people undergoing major orthopaedic surgery (such as joint replacement), with postoperative rates of around 1% despite anticoagulation treatment [Di Nisio, 2016]. 
  • Significant immobility, for example, due to hospitalization, limb paralysis, or bed rest.
    • Bed rest (longer than 5 days) is present in 28% of people with confirmed PE.
  • Previous VTE — there is a lifelong risk of VTE recurrence after a first episode of PE. About 25% of people with PE have had a previous thromboembolic event. 
  • Active cancer — this is present in 22% of people with PE.
    • The risk of VTE in people with cancer varies with different types of cancer; haematological, lung, gastrointestinal, pancreatic, and brain cancers carry the highest risk. In addition, cancer is a strong risk factor for all-cause mortality following an episode of VTE. 
  • Antiphospholipid antibody syndrome and other thrombotic disorders.   
    • Antiphospholipid antibody syndrome is reported in up to 14% of people with a VTE.  
  • Recent trauma or lower limb fracture — this is present in 11% of people with confirmed PE.
  • Recent myocardial infarction (within the last 3 months). 
  • Increasing age — the incidence and mortality from PE increase with age, and the age-specific mortality doubles for every 10 years starting at 25 years. 
  • Family history of VTE — there is a significantly increased rate of VTE among first-degree siblings. This risk is increased more than 20-fold in people with two affected siblings. 
  • Pregnancy and postnatal period (particularly 6 weeks postpartum) — the risk of antenatal VTE is four to five-fold higher in pregnant women than in nonpregnant women of the same age (although the absolute risk remains low at around 1 in 1000 pregnancies). The puerperium is the time of highest risk, with estimates of relative risk of approximately 20-fold [RCOG, 2015].
• Other risk factors include:
  • The use of combined oral contraception (within the previous year) or hormone replacement therapy.
    • Combined oral contraceptives (containing both an oestrogen and a progestogen) are associated with an approximately two- to six-fold increase in VTE risk over baseline, but in general the absolute risk remains low. 
    • The increased risk associated with use of HRT varies widely and depends on the formulation. 
  • Cigarette smoking. 
  • Indwelling central vein catheter.
  • Long-duration travel (for example air travel).
  • Obesity (body mass index greater than 30 kg/m²). 
  • One or more significant medical comorbidities, for example:
    • Behçet's disease.
    • Chronic dialysis.
    • Chronic obstructive pulmonary disease. 
    • Congestive heart failure. 
    • Diabetes mellitus. 
    • Inflammatory bowel disease.
    • Myeloproliferative disorders.
    • Nephrotic syndrome.
    • Paroxysmal nocturnal haemoglobinuria.
    • Sepsis. 
    • Superficial venous thrombosis.
    • Varicose veins.

[Konstantinides, 2020; BMJ Best Practice, 2022] 

What are the complications?

• Pulmonary embolism (PE) is a major cause of mortality, morbidity, and hospitalization.
• In 2021, PE was the underlying cause of death in 2638 people in England and Wales.  
  • The mortality rate is lower in those who are haemodynamically stable and higher in those who present cardiorespiratory arrest. Severe cases of PE can lead to collapse and/or sudden death.  
  • About 5-10% of people present as haemodynamically unstable, and the risk of early death is greater than 15%. 
  • Haemodynamically stable people with evidence of heart strain and/or myocardial infarction are at increased risk, with early mortality of 3-15%. 
• An epidemiological model constructed to assess the number of venous thromboembolism (VTE) events and associated morbidity and mortality in Europe estimated that in 2004, over 370,000 deaths were related to VTE in six European countries (with a total population of 454.4 million).
  • Of these cases, 34% died suddenly or within a few hours of the acute event before therapy could be initiated or take effect, 59% were deaths resulting from PE that remained undiagnosed during life, and 7% of the people who died early were correctly diagnosed with PE before death.
• Thrombosis and thromboembolism is the leading cause of direct deaths occurring within 42 days of the end of pregnancy in the UK.
  • In 2018–2020, 29 women died of thrombosis and thromboembolism during pregnancy or up to 6 weeks after the end of pregnancy. The maternal mortality rate was 1.38 per 100,000 pregnancies. 
• Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare and potentially fatal complication of PE, with a reported cumulative incidence of 0.1–9.1% within the first 2 years after a symptomatic PE event. 
  • In people with CTEPH, fibrous tissue replaces residual emboli over months or years, leading to chronic obstruction of the pulmonary arterial vasculature, progressive increases in pulmonary arterial pressure, and, if untreated, right heart failure. 
  • Risk factors include large thrombus mass, thrombophilic disorders, history of splenectomy, history of cancer, myeloproliferative disorders, inflammatory bowel disease, and previous episodes of VTE. 

[Konstantinides, 2020; Stein, 2020; MBRRACE-UK, 2022; ONS, 2022; NICE, 2023]

What is the prognosis?

• If pulmonary embolism (PE) is left untreated, the prognosis is poor and there is a significant risk of death. 
• Following treatment, some people develop complications, such as chronic thromboembolic pulmonary hypertension, or experience persistent or deteriorating dyspnoea, and poor physical performance for 6 months to 3 years after a PE.  
  • Independent predictors of reduced functional exercise capacity and quality of life over time included female sex, higher body mass index, history of lung disease, higher pulmonary artery systolic pressures on the 10-day echocardiogram, and higher main pulmonary artery diameter on the baseline computed tomography pulmonary angiogram CTPA).
• There is a greater risk of recurrence of PE in people with risk factors that are not transient or reversible and after multiple episodes of venous thromboembolism (VTE) — the risk for long-term recurrence can be classified as low, intermediate or high depending on the risk factor:
  • Low (less than 3% per year) — surgery with general anaesthesia for over 30 minutes, confined to bed in hospital for 3 days or more, trauma with fractures.  
  • Intermediate (3-8% per year) — minor surgery (general anaesthesia for less than 30 minutes), admission to hospital for less than 3 days with an acute illness, oestrogen therapy or contraception, pregnancy or puerperium, leg injury without fracture associated with reduced mobility for 3 days or more, long-haul flight.
  • High (more than 8% per year) — active cancer, one or more previous episodes of VTE in the absence of a major transient reversible risk factor, antiphospholipid antibody syndrome.
• Recurrence rates may be up to 10% in the first year after withdrawal of anticoagulation treatment. 
  • One study of people with a first episode of PE found that the recurrence rate after discontinuation of treatment was 2.5% per year after PE associated with transient risk factors, compared with 4.5% per year after PE occurring in the absence of known cancer, known thrombophilia, or any transient risk factor.
• The frequency of recurrence does not appear to depend on the clinical presentation of the first event (that is, whether it was a DVT or PE), but recurrent VTE is likely to occur in the same clinical form as the first event.

 [Konstantinides, 2020; BMJ Best Practice, 2022; NICE, 2023]

When should I suspect pulmonary embolism?

• Signs and symptoms of pulmonary embolism are non-specific, but symptoms typically have a sudden onset.
• Suspect pulmonary embolism (PE) in a person with any of the following:
  • Dyspnoea — this is the most common feature and is present in 50% of people with PE. 
    • It may be acute and severe in central PE, but mild and transient in a small peripheral PE.
  • Haemoptysis. 
  • Pleuritic chest pain — present in 39% of people with PE.
    • Pain is normally localised to one side. 
  • Syncope or pre-syncope. 
  • Tachypnoea — present in 21-39% of people with PE.  
  • Features of deep vein thrombosis (DVT) — for more information, see the CKS topic on Deep vein thrombosis. 
• Other symptoms that may be present include:
  • Retrosternal chest pain (due to right ventricular ischaemia). 
  • Cough — present in approximately 23% of people with PE.  
• Other signs that may be present include:
  • Elevated jugular venous pressure. 
  • Fever. 
  • Gallop rhythm, a wide split-second heart sound, tricuspid regurgitant murmur. 
  • Hypotension (systolic blood pressure less than 90 mmHg) and cardiogenic shock — haemodynamic instability is rare and indicates central and/or extensive PE with severely reduced haemodynamic reserve.
  • Hypoxia.
  • Pleural rub. 
  • Tachycardia (heart rate greater than 100 beats per minute). 
• The presence of risk factors, such as pregnancy, previous DVT or PE, active cancer, or recent surgery, makes the diagnosis of PE more likely.
• Be aware that PE may be completely asymptomatic and be discovered incidentally when assessing for another condition. 
• If PE is suspected:
  • Carry out an assessment of their general medical history, a physical examination, and, where necessary, investigations (such as a chest X-ray or electrocardiogram [ECG]) to: 
    • Exclude other causes of symptoms, including other respiratory conditions (such as pneumothorax and pneumonia) and cardiac causes (such as acute coronary syndrome and acute congestive heart failure).
    • Assess for risk factors (such as pregnancy and immobilization). 
  • Do not delay management for results of a chest X-ray or ECG. 
    • A chest X-ray or ECG are not diagnostic for PE, but they may be useful in the differential diagnosis. 
    • Chest X-ray features that may be present in people with PE include atelectasis, pleural effusion, or elevation of a hemidiaphragm. 
    • ECG signs that may be present in people with PE include sinus tachycardia, non-specific ST-segment and T-wave abnormalities, right axis deviation, incomplete or complete right bundle-branch block, and, less commonly, T-wave inversion in leads V1–V3, P pulmonale, or the classical S1, Q3, T3 (S wave in lead 1, Q wave in lead 3, and T-wave inversion in lead 3). 
• If clinical suspicion is low, consider using the pulmonary embolism rule-out criteria (PERC) to help determine whether any further investigations are needed. 
  • Be aware that PERC has not been validated in people with COVID-19.

What else might it be?

• Conditions that can cause similar symptoms to pulmonary embolism (PE) include:
  • Other respiratory conditions, such as:
    • Acute bronchitis.
    • Acute exacerbation of asthma. For more information, see the CKS topic on Asthma.
    • Acute exacerbation of chronic obstructive pulmonary disease (COPD). For more information, see the CKS topic on Chronic obstructive pulmonary disease.
    • Pneumonia.
    • Pneumothorax. 
  • Cardiac causes, such as:
    • Acute coronary syndrome. 
    • Acute congestive heart failure. 
    • Aortic dissection. 
    • Cardiac tamponade.
    • Myocardial infarction. For more information, see the CKS topic on MI - secondary prevention.
    • Pericarditis. 
    • Unstable angina. For more information, see the CKS topic on Angina.
  • Musculoskeletal chest pain. Note that chest pain with chest wall palpation occurs in up to 20% of people with confirmed PE.
  • Gastro-oesophageal reflux disease. For more information, see the CKS topic on Dyspepsia - proven GORD.
  • Any cause for collapse, such as:
    • Cardiac arrhythmias. For more information, see the CKS topic on Atrial fibrillation.
    • Cerebrovascular disorders. For more information, see the CKS topic on Stroke and TIA.
    • Orthostatic (postural) hypotension.
    • Seizures. For more information, see the CKS topic on Epilepsy.
    • Vasovagal syncope.
  • Panic disorder. For more information, see the CKS topic on Generalized anxiety disorder.
• Non-thrombotic sources of emboli include:
  • Air — admitted during surgery or from other communication between the environment and the venous system. 
  • Amniotic fluid in pregnant women. 
  • Fat — from pelvic or long-bone fractures. 
  • Foreign material — silicone, broken catheters, guide wires, vena cava filters, embolization coils, and endovascular stent components.
  • Sepsis — this is rare, but most commonly associated with right-sided endocarditis. Risk factors include intravenous drug misuse, infected indwelling catheters or pacemaker wires. 
  • Tumours — most commonly prostate, gastrointestinal, liver, kidney, and breast cancers.

Scenario: Suspected pulmonary embolism

From age 18 years onwards.

Scenario: Confirmed pulmonary embolism

From age 18 years onwards.

Parenteral anticoagulants

• The parenteral anticoagulants licensed for the treatment of pulmonary embolism are [BNF, 2023]: 
  • Low molecular weight heparins (dalteparin, enoxaparin, and tinzaparin).
  • Fondaparinux, a synthetic pentasaccharide that inhibits activated factor X.

Oral anticoagulants

• The direct oral anticoagulants (DOACs) licensed for the treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE), and prevention of recurrent DVT and PE in adults are:
  • Apixaban.
  • Dabigatran.
  • Edoxaban.
  • Rivaroxaban.
• Warfarin is also licensed for the treatment and prophylaxis of DVT and PE. 

[NICE, 2013; NICE, 2014; NICE, 2015a; NICE, 2015b; EMC, 2022e] 

Search strategy

Scope of search

A literature search was conducted for guidelines and systematic reviews on primary care management of pulmonary embolism (PE).

Search dates

January 2019 - August 2023

Key search terms

The terms listed below are the core search terms that were used for EBSCOhost MEDLINE. The strategy was adapted for The Cochrane Library databases. 

S4     S1 OR S2 OR S3
S3    AB pulmonary N0 thromboembolism* OR TI pulmonary N0 thromboembolism* 
S2    AB pulmonary N0 embolism* OR TI pulmonary N0 embolism* 
S1    (MH "Pulmonary Embolism+") 

Sources of guidelines

• National Institute for Health and Care Excellence (NICE)
• Scottish Intercollegiate Guidelines Network (SIGN)
• Royal College of Physicians
• Royal College of General Practitioners
• Royal College of Nursing
• NICE Evidence
• World Health Organization
• Guidelines International Network
• TRIP database
• Agency for Healthcare Research and Quality
• Institute for Clinical Systems Improvement
• National Health and Medical Research Council (Australia)
• Royal Australian College of General Practitioners
• British Columbia Medical Association
• Canadian Medical Association
• Alberta Medical Association
• Michigan Quality Improvement Consortium
• Singapore Ministry of Health
• National Resource for Infection Control
• RefHELP NHS Lothian Referral Guidelines
• Medline (with guideline filter)
• Driver and Vehicle Licensing Agency
• NHS Health at Work (occupational health practice)

Sources of systematic reviews and meta-analyses

• The Cochrane Library:
  • Systematic reviews
  • Protocols
  • Database of Abstracts of Reviews of Effects
• Medline (with systematic review filter)
• EMBASE (with systematic review filter)

Sources of health technology assessments and economic appraisals

• NIHR Health Technology Assessment programme
• The Cochrane Library:
  • NHS Economic Evaluations
  • Health Technology Assessments
• Canadian Agency for Drugs and Technologies in Health
• International Network of Agencies for Health Technology Assessment

Sources of randomized controlled trials

• The Cochrane Library:
  • Central Register of Controlled Trials
• Medline (with randomized controlled trial filter)
• EMBASE (with randomized controlled trial filter)

Sources of evidence based reviews and evidence summaries

• Bandolier
• Drug and Therapeutics Bulletin
• TRIP database
• Central Services Agency COMPASS Therapeutic Notes

Sources of national policy

• Department of Health
• Health Management Information Consortium (HMIC)

Patient experiences

• Healthtalk
• BMJ - Patient Journeys

Sources of medicines information

The following sources are used by CKS pharmacists and are not necessarily searched by CKS information specialists for all topics. Some of these resources are not freely available and require subscriptions to access content.

• British National Formulary (BNF)
• electronic Medicines Compendium (eMC)
• European Medicines Agency (EMEA)
• LactMed
• Medicines and Healthcare products Regulatory Agency (MHRA)
• REPROTOX
• Scottish Medicines Consortium
• Stockley's Drug Interactions
• TERIS
• TOXBASE
• Micromedex
• UK Medicines Information

Stakeholder engagement

Our policy

The external review process is an essential part of CKS topic development. Consultation with a wide range of stakeholders provides quality assurance of the topic in terms of:

• Clinical accuracy.
• Consistency with other providers of clinical knowledge for primary care.
• Accuracy of implementation of national guidance (in particular NICE guidelines).
• Usability.

Principles of the consultation process

• The process is inclusive and any individual may participate.
• To participate, an individual must declare whether they have any competing interests or not. If they do not declare whether or not they have competing interests, their comments will not be considered.
• Comments received after the deadline will be considered, but they may not be acted upon before the clinical topic is issued onto the website.
• Comments are accepted in any format that is convenient to the reviewer, although an electronic format is encouraged.
• External reviewers are not paid for commenting on the draft topics.
• Discussion with an individual or an organization about the CKS response to their comments is only undertaken in exceptional circumstances (at the discretion of the Clinical Editor or Editorial Steering Group).
• All reviewers are thanked and offered a letter acknowledging their contribution for the purposes of appraisal/revalidation.
• All reviewers are invited to be acknowledged on the website. All reviewers are given the opportunity to feedback about the external review process, enabling improvements to be made where appropriate.

Stakeholders

• Key stakeholders identified by the CKS team are invited to comment on draft CKS topics. Individuals and organizations can also register an interest to feedback on a specific topic, or topics in a particular clinical area, through the Getting involved section of the Clarity Informatics website.
• Stakeholders identified from the following groups are invited to review draft topics:
  • Experts in the topic area.
  • Professional organizations and societies (for example, Royal Colleges).
  • Patient organizations, Clarity has established close links with groups such as Age UK and the Alzheimer’s Society specifically for their input into new topic development, review of current topic content and advice on relevant areas of expert knowledge.
  • Guideline development groups where the topic is an implementation of a guideline.
  • The British National Formulary team.
  • The editorial team that develop MeReC Publications.
• Reviewers are provided with clear instructions about what to review, what comments are particularly helpful, how to submit comments, and declaring interests.

Patient engagement

Clarity Informatics has enlisted the support and involvement of patients and lay persons at all stages in the process of creating the content which include:

• Topic selection
• Scoping of topic
• Selection of clinical scenarios
• First draft internal review
• Second draft internal review
• External review
• Final draft and pre-publication

Our lay and patient involvement includes membership on the editorial steering group, contacting expert patient groups, organizations and individuals.

Evidence exclusion criteria

Our policy

Scoping a literature search, and reviewing the evidence for CKS is a methodical and systematic process that is carried out by the lead clinical author for each topic. Relevant evidence is gathered in order that the clinical author can make fully informed decisions and recommendations. It is important to note that some evidence may be excluded for a variety of reasons. These reasons may be applied across all CKS topics or may be specific to a given topic.

Studies identified during literature searches are reviewed to identify the most appropriate information to author a CKS topic, ensuring any recommendations are based on the best evidence. We use the principles of the GRADE and PICOT approaches to assess the quality of published research. We use the principles of AGREE II to assess the quality of published guidelines.

Standard exclusions for scoping literature:

• Animal studies
• Original research is not written in English

Possible exclusions for reviewed literature:

• Sample size too small or study underpowered
• Bias evident or promotional literature
• Population not relevant
• Intervention/treatment not relevant
• Outcomes not relevant
• Outcomes have no clear evidence of clinical effectiveness
• Setting not relevant
• Not relevant to UK
• Incorrect study type
• Review article
• Duplicate reference

Organizational, behavioural and financial barriers

Our policy

The CKS literature searches take into consideration the following concepts, which are discussed at the initial scoping of the topic.

• Feasibility
  • Studies are selected depending on whether the intervention under investigation is available in the NHS and can be practically and safely undertaken in primary care.
• Organizational and Financial Impact Analysis
• Studies are selected and evaluated on whether the intervention under investigations may have an impact on local clinical service provision or national impact on cost for the NHS. The principles of clinical budget impact analysis are adhered to, evaluated and recorded by the author. The following factors are considered when making this assessment and analysis.
  • Eligible population
  • Current interventions
  • Likely uptake of new intervention or recommendation
  • Cost of the current or new intervention mix
  • Impact on other costs
  • Condition-related costs
  • In-direct costs and service impacts
  • Time dependencies
• Cost-effectiveness or cost-benefit analysis studies are identified where available. 

We also evaluate and include evidence from NICE accredited sources which provide economic evaluations of recommendations, such as NICE guidelines. When a recommended action may not be possible because of resource constraints, this is explicitly indicated to healthcare professionals by the wording of the CKS recommendation.

Declarations of interest

Our policy

Clarity Informatics requests that all those involved in the writing and reviewing of topics, and those involved in the external review process to declare any competing interests. Signed copies are securely held by Clarity Informatics and are available on request with the permission of the individual. A copy of the declaration of interest form which participants are asked to complete annually is also available on request. A brief outline of the declarations of interest policy is described here and full details of the policy is available on the Clarity Informatics website. Declarations of interests of the authors are not routinely published, however competing interests of all those involved in the topic update or development are listed below. Competing interests include:

• Personal financial interests
• Personal family interest
• Personal non-financial interest
• Non-personal financial gain or benefit

Although particular attention is given to interests that could result in financial gains or losses for the individual, competing interests may also arise from academic competition or for political, personal, religious, and reputational reasons. An individual is not obliged to seek out knowledge of work done for, or on behalf of, the healthcare industry within the departments for which they are responsible if they would not normally expect to be informed.

Who should declare competing interests?

Any individual (or organization) involved in developing, reviewing, or commenting on clinical content, particularly the recommendations should declare competing interests. This includes the authoring team members, expert advisers, external reviewers of draft topics, individuals providing feedback on published topics, and Editorial Steering Group members. Declarations of interest are completed annually for authoring team and editorial steering group members, and are completed at the start of the topic update and development process for external stakeholders.

Competing interests declared for this topic:

None.