Changes

November 2023 — minor update. To align with changes in the NICE guidelines Hypertension in adults: diagnosis and assessment [NG136] and Transient loss of consciousness ('blackouts') in over 16s [CG109]. Previous recommendation to assess a person with possible orthostatic hypotension was to measure blood pressure after three minutes standing has been revised to assess after at least 1 minute of standing. 

Update

Goals

To support primary healthcare professionals to:

• Assess a person to determine the likely underlying cause(s) of a blackout or syncope, where possible.
• Arrange emergency hospital admission or specialist referral if clinically indicated.
• Offer advice on self-management if clinically appropriate, for example, if vasovagal syncope, situational syncope, or orthostatic hypotension are suspected.

Outcome measures

Audit criteria

QOF indicators

QIPP - Options for local implementation

NICE quality standards

The NICE quality standards relevant for this CKS topic are:

Statement 1. People who have had a suspected transient loss of consciousness have an initial assessment to record details of the event, clinical history, and physical examination.

Statement 2. People who have had a transient loss of consciousness have a 12‑lead electrocardiogram (ECG) during the initial assessment.

Statement 3. People who have had a transient loss of consciousness and one or more 'red flag' signs or symptoms identified have an urgent specialist cardiovascular assessment within 24 hours of the initial assessment.

Statement 4. People who have had a transient loss of consciousness are not routinely offered an electroencephalogram to investigate the event.

Statement 5. People who have had a transient loss of consciousness are advised not to drive while they are awaiting specialist assessment.

Statement 6. People with a suspected cardiac arrhythmic cause of syncope are offered an ambulatory ECG as a first‑line specialist cardiovascular investigation.

[NICE, 2022]

What is it?

• The term 'blackout' is sometimes used to describe transient loss of consciousness with complete recovery [NICE, 2014] [Brignole, 2018b].
  • Transient loss of consciousness is defined as 'a state of real or apparent loss of consciousness with loss of awareness, characterized by amnesia for the period of unconsciousness, abnormal motor control, loss of responsiveness, and a short duration' [Brignole, 2018a].
  • The European Society of Cardiology (ESC) notes that the term blackout is imprecise but may be used in communication with patients [Brignole, 2018b].
• The ESC defines syncope as 'transient loss of consciousness due to cerebral hypoperfusion, characterized by a rapid onset, short duration, and spontaneous complete recovery' [Brignole, 2018a].
  • The main causes of syncope are 'reflex' (neurally mediated) such as vasovagal syncope, situational syncope, or carotid sinus syndrome; orthostatic hypotension; and cardiac syncope [Brignole, 2018a]. See the section on Causes for more information.
  • The term 'presyncope' describes symptoms and signs that occur before loss of consciousness in syncope [Brignole, 2018a].
  • The term 'blackout' differs from 'coma', which defines a state of prolonged unresponsive loss of consciousness with a longer duration than transient loss of consciousness [Brignole, 2018a].

What causes it?

There are multiple possible causes of blackouts and syncope, and symptoms may be due to more than one mechanism [NICE, 2014]. Be aware that in up to one-third of cases, the underlying cause may not be identified [D'Ascenzo, 2013].

Potentially life-threatening [Brignole, 2018a] 

• Acute myocardial infarction/ischaemia. See the CKS topics on Chest pain and Cardiac arrest - out of hospital care for more information.
• Cardiac arrhythmia — suggested by palpitations; may be associated with breathlessness, chest pain, and lightheadedness. See the CKS topic on Palpitations for more information.
• Head trauma. See the CKS topic on Head injury for more information.
• Pulmonary embolism. See the CKS topic on Pulmonary embolism for more information.
• Occult haemorrhage — suggested by recent trauma or clinical features of gastrointestinal bleeding (haematemesis or melaena); ruptured aortic aneurysm (suggested by severe abdominal and back pain) or acute aortic dissection (suggested by severe chest and/or back pain); cardiac tamponade (distended neck veins, chest pain radiating to neck/shoulders/back relieved by sitting forward); subarachnoid haemorrhage (severe thunderclap headache, focal neurological signs); ruptured ovarian cyst or ectopic pregnancy; retroperitoneal haemorrhage, or ruptured spleen (usually traumatic). See the CKS topics on Chest pain, Dyspepsia - proven peptic ulcer, Ectopic pregnancy, and Headache - assessment for more information.
• Vertebrobasilar transient ischaemic attack (TIA) — suggested by focal neurological symptoms and signs. Does not usually present with loss of consciousness. See the CKS topic on Stroke and TIA for more information.
  • Subclavian steal syndrome — may present with a TIA and focal neurological signs due to re-routing of blood flow to the arm through the vertebral artery due to proximal stenosis or occlusion of the subclavian artery (very rare).
• Status epilepticus. See the CKS topic on Epilepsy for more information.
• Adrenal crisis. See the CKS topic on Addison's disease for more information.

Syncope

• Vasovagal syncope (uncomplicated 'faint') [NICE, 2014] [Brignole, 2018a] 
  • Suspect if no features to suggest an alternative diagnosis, and the 3 'P's are present:
    • Posture — typically after prolonged standing; less common after sitting. Similar episodes may be prevented by lying down.
    • Provoking factors — fear; pain (somatic or visceral); instrumentation; blood phobia; unpleasant sight, sound or smell; crowded or hot places; dehydration.
    • Progressive prodrome — such as pallor, sweating, and/or nausea or vomiting.
    • Note: brief myoclonus can occur during uncomplicated vasovagal syncope and is not necessarily diagnostic of epilepsy.
  • Typically there is a long history of recurrent syncope occurring before the age of 40 years.
• Situational syncope [NICE, 2014] [Brignole, 2018a] 
  • Suspect if no features to suggest an alternative diagnosis, and syncope consistently occurs during or immediately after specific triggers:
    • Straining during micturition (usually while standing).
    • Swallowing, defaecation.
    • Coughing, sneezing.
    • Post-exercise, laughing.
• Carotid sinus syndrome [NICE, 2014] [Brignole, 2018a] [Thijs, 2021] 
  • Suspect if syncope is triggered by head rotation or pressure on the carotid sinus (for example shaving or wearing tight collars), or if unexplained syncope or falls in a person aged 40 years or more (more common in men).
    • This is a form of neurally-mediated syncope due to hypersensitivity of the carotid sinus baroreceptor, where pressure on one or other carotid artery causes syncope via a reflex bradycardic and/or hypotensive response.
  • There is typically a ventricular pause lasting more than 3 seconds and/or a fall in systolic blood pressure of more than 50 mmHg.
• Orthostatic hypotension (OH) [Brignole, 2018a] [Brignole, 2018b] [Wieling, 2022]
  • Suspect if no features to suggest an alternative diagnosis and a typical history:
    • Syncope occurs while or after standing; prolonged standing; standing after exertion; after eating (post-prandial hypotension, particularly after carbohydrate-rich meals or drinking alcohol); straining; after exercise (exercise-induced venous pooling); and after prolonged bed rest (physical deconditioning). May be worse in the morning or in hot environments.
    • There may be symptoms of lightheadedness, dizziness, fatigue, visual disturbance; shoulder and neck pain ('coat hanger pain'), or it may present with recurrent or unexplained falls.
    • Symptoms are absent while lying down, and less severe or absent when sitting.
    • There may be a temporal relationship with the initiation or dose change of drugs such as alpha-blockers, beta-blockers, tricyclic antidepressants, antihypertensives, diuretics, nitrates, levodopa or dopaminergic agonists.
  • Significant OH is defined as a progressive and sustained fall in systolic blood pressure from a baseline value more than or equal to 20 mmHg, or diastolic blood pressure more than or equal to 10 mmHg, or a decrease in systolic blood pressure to less than 90 mmHg.
    • It may be non-neurogenic due to volume depletion, heart failure, cardiac arrhythmias, or advanced valvular heart disease; or neurogenic due to autonomic failure in underlying conditions such as diabetes mellitus, Parkinson's disease, Lewy body dementia, spinal cord injuries, autonomic neuropathy. Note: neurogenic causes of OH may be associated with supine hypertension.
  • Other causes of orthostatic intolerance include postural orthostatic tachycardia syndrome (PoTS), where there is an inappropriate orthostatic heart rate increase (by more than 30 beats per minute, or increasing to more than 120 beats per minute) within 10 minutes of standing, without a fall in blood pressure. It may be immune-mediated, due to excessive venous pooling, or a hyperadrenergic state.
• Cardiac syncope [NICE, 2014] [Brignole, 2018a] 
  • Suspect if no features to suggest an alternative diagnosis and a typical history and/or electrocardiogram (ECG) findings:
    • Syncope during exertion or when supine.
    • Sudden-onset palpitations immediately followed by syncope.
    • New or unexplained breathlessness.
    • Comorbid heart failure.
    • Blackout without prodromal symptoms in people aged over 65 years.
    • A heart murmur on physical examination.
    • A family history of sudden unexplained death in a person less than 40 years of age and/or an inherited cardiac condition.
  • ECG abnormalities may be due to arrhythmia (such as sinus bradycardia 40–50 beats per minute; slow atrial fibrillation 40–50 beats per minute; AV block; VT or rapid paroxysmal SVT; long or short QT interval; Brugada syndrome (ST segment elevation); Wolff-Parkinson-White syndrome); structural heart disease (such as severe aortic stenosis, hypertrophic cardiomyopathy, cardiac masses, prosthetic valve dysfunction); coronary artery disease; or pulmonary hypertension. See the CKS topic on Palpitations for more information.
  • Cardiac syncope is usually secondary to a decrease in cardiac output.

Non-syncope

• Epilepsy or seizure [Brignole, 2018a] [Thijs, 2021]
  • Forms of epilepsy which may cause transient loss of consciousness include tonic, clonic, tonic-clonic, and atonic generalized seizures. See the CKS topic on Epilepsy for detailed information on possible clinical presentations.
• Psychogenic [Brignole, 2018a] 
  • Psychogenic pseudosyncope (PPS) which may resemble syncope but is not associated with cerebral hypoperfusion. See the section on Differential diagnosis for more information.
  • Psychogenic non-epileptic seizures (PNES) which may resemble epileptic seizures. See the section on Differential diagnosis for more information.

How common is it?

The prevalence of blackouts and syncope varies depending on the underlying cause, and the true incidence is difficult to estimate due to variations in definition, population prevalence, and under-reporting in the general population [Kenny, 2013] [Brignole, 2018b].

• A retrospective study of UK primary care data from two GP practices over a 6-month period (n = 16,911) found the incidence of first presentation of blackout was 3.4 per 1,000 patients per year. It states that in the UK, 50% of people will experience a blackout at some point in their life, and blackouts are responsible for 3% of emergency department attendances and 1% of hospital admissions [Kavi, 2017].
• A retrospective observational study of patients with vasovagal syncope confirmed on head-up tilt table testing in a tertiary centre over a 10-year period (n = 1,060 consecutive patients) found [Duncan, 2010]:
  • A bimodal age distribution with a small peak at 20–29 years (9% of cases) and a larger peak at 70–79 years (23.3% of cases).
  • People over the age of 60 years were more likely to present with unexplained falls.
• A systematic review and meta-analysis of 26 studies of people aged 60 years or more in the community (n = 24,967) and in long-term care settings (n = 2,694) found [Saedon, 2020]:
  • The pooled prevalence of orthostatic hypotension was 22.2% in the community and 23.9% in long-term care settings.
• Expert opinion in a review article notes that the lifetime cumulative incidence of syncope in women is almost twice that of men, with a cumulative incidence ranging from 5% of women aged 20–29 years, up to 50% of women aged 80 years and over [Kenny, 2013].
• A large international meta-analysis of 11 studies (n = 43,315 people presenting to emergency departments with syncope) found [D'Ascenzo, 2013]:
  
  • 42% of people were admitted to hospital following emergency department assessment.
  • The risk of death was 4.4%, mainly related to cardiovascular disease.
  • One-third of participants were discharged without a diagnosis.
• An epidemiological study in Utah, USA, found the yearly prevalence of syncope needing medical attention was 9.5 per 1000 inhabitants, and the prevalence increased with age, with 40 per 1000 inhabitants aged more than 80 years affected [Malasana, 2011].

What is the prognosis?

The prognosis of a person with blackouts or syncope depends on the underlying cause and mechanism [Sutton, 2021].

• The European Society of Cardiology (ESC) guidelines note that low-risk and younger people with vasovagal syncope and situational syncope who have had structural heart disease or an arrhythmia excluded as a cause of symptoms generally have an excellent prognosis [Brignole, 2018a].
  
  • It states that syncope recurs in less than 50% of people within 1–2 years, particularly if there is no clear anatomical cause, such as reflex syncope and unexplained syncope.
• Orthostatic hypotension is associated with a two-fold higher risk of death due to the severity of comorbidities compared with the general population [Brignole, 2018a].
• A prospective study of people with syncope followed up for 12 months (n = 204) found [Kapoor, 1983]:
  • The mortality rate in people with an underlying cardiovascular cause was significantly higher than in people with a non-cardiovascular cause (30% and 12% respectively).
  • The incidence of sudden death was significantly higher in people with an underlying cardiovascular cause than in people with a non-cardiovascular cause (24% and 4% respectively).
• The ESC guidelines note that sudden cardiac death rates in people aged less than 35 years is 1–3 per 100,000 [Brignole, 2018a].
  • Structural heart disease is the major risk factor for sudden cardiac death and overall mortality in people with syncope [Brignole, 2018b].

What are the complications?

Possible complications of a blackout or syncope episode depend on the underlying cause, and may include:

• Injury and physical trauma including fractures — more common if a prodrome is absent or short, with no or insufficient warning symptoms for the person to act to prevent injury [Brignole, 2018b; Dani, 2021; Wieling, 2022].
• Falls. See the CKS topic on Falls - risk assessment for more information [Brignole, 2018b; Dani, 2021; Wieling, 2022].
• Loss of confidence and social isolation, disruption to school and work activity, and impact on driving [Brignole, 2018b].
• Anxiety and depression, fear of falling. See the CKS topics on Generalized anxiety disorder and Depression for more information [Brignole, 2018b; Wieling, 2022].
• Road traffic collisions — road traffic collisions resulting from blackouts and syncope are 2–3 times more common than those resulting from seizures [DVLA, 2022].

How should I assess a person presenting with a blackout or syncope?

If a person presents with blackout or syncope and a suspected life-threatening cause, has not fully regained consciousness, or has a potentially serious injury, arrange emergency hospital admission or specialist referral, depending on clinical judgement. If clinically appropriate, continue to assess the person in primary care and arrange ongoing management.

• Examine the person.
  • Assess vital signs including pulse rate, rhythm, and volume; respiratory rate; oxygen saturation; temperature; and blood pressure (BP), and monitor as clinically indicated.
  • Measure blood pressure with the person lying on their back (or consider a seated position, if it is inconvenient to measure blood pressure with the person lying down). Repeat BP measurements while active standing for at least 1 minute to assess for orthostatic hypotension (OH) or postural orthostatic tachycardia syndrome (PoTS).
    • OH is defined as a progressive and sustained fall in systolic blood pressure from baseline of more than or equal to 20 mmHg, or diastolic blood pressure of more than or equal to 10 mmHg, or a decrease in systolic blood pressure to less than 90 mmHg that reproduces spontaneous symptoms.
    • PoTS is defined as an orthostatic heart rate increase (more than 30 beats per minute, or increasing to more than 120 beats per minute) within 10 minutes of active standing, in the absence of OH which reproduces spontaneous symptoms.
  • Check blood glucose level to assess for hypoglycaemia or hyperglycaemia.
  • Assess for the presence of a heart murmur.
  • Perform a neurological examination to assess cognitive function, sensory, motor, speech, and visual focal deficits including parkinsonism, ataxia, and peripheral neuropathy.
• Ask the person (if possible) and any first-hand witnesses about what happened before, during, and after the event, to help determine the possible underlying cause(s) and appropriate management.
  • The circumstances of the event.
    • Note: a person may present with collapse or unexplained falls, especially if there is no recollection of the fall itself and no evidence of protective measures taken by the person, such as extending the hands (more common in the elderly).
  • The person's posture immediately before the event (standing/sitting/supine).
  • Any prodromal symptoms, such as sweating or feeling warm/hot (may suggest vasovagal); déjà vu or jamais vu (may suggest epilepsy). See the CKS topic on Epilepsy for more information.
  • The person's appearance during the episode (such as pallor, eyes open or closed) — eyes closed during loss of consciousness is more likely to suggest psychogenic pseudosyncope (PPS) or psychogenic non-epileptic seizures (PNES).
  • Any movement during the event such as prolonged limb-jerking or unusual posturing (suggests epilepsy) and its duration.
    • Note: brief myoclonus can occur during uncomplicated vasovagal syncope and is not necessarily diagnostic of epilepsy.
  • Any tongue-biting (lateral tongue suggests epilepsy; tip of tongue suggests vasovagal syncope); loss of bladder or bowel control (may suggest epilepsy).
  • Any associated symptoms such as new or unexplained breathlessness, palpitations, chest discomfort, abdominal pain, headache (suggests potentially serious underlying cause); lightheadedness, dizziness, fatigue, visual disturbance (if worse on standing and relieved by sitting/lying down may suggest OH or vasovagal); constipation, urinary symptoms, or erectile dysfunction (may suggest an autonomic neurological cause).
  • Injury occurring during the event (site and severity).
  • Duration of loss of consciousness — duration less than 30 seconds may suggest syncope; duration more than one minute is more suggestive of epilepsy than syncope; duration more than 5 minutes suggests PPS or PNES.
  • Any confusion or amnesia after regaining consciousness (if this lasts minutes this may suggest epilepsy).
  • Weakness down one side of the body during the recovery period (may suggest vertebrobasilar transient ischaemic attack). See the CKS topic on Stroke and TIA for more information.
  • Triggers or provoking factors such as head movements or pressure on the neck (carotid sinus syndrome); during exercise (may be a cardiac cause); after exercise (may be vasovagal or OH); after prolonged standing (suggests vasovagal or OH); after meals (suggests OH or vasovagal); pain (suggests vasovagal); consistently provoked by micturition, defaecation, coughing, or swallowing (suggests situational syncope).
  • Intercurrent illness (haemorrhage, diarrhoea and vomiting, low fluid intake increases risk of volume depletion).
  • Details of any previous episodes or recurrent/unexplained falls, including number, frequency, and circumstances.
  • Previous medical history including structural or coronary artery disease.
  • Current medication including polypharmacy and any drugs which may cause reflex syncope or orthostatic intolerance.
  • Any family history of cardiac disease including sudden cardiac or unexplained death in a person aged younger than 40 years, or an inherited cardiac condition (may suggest a high-risk cardiac cause).
  • Smoking and alcohol use — alcohol may worsen symptoms of reflex syncope and OH.
• Arrange a 12-lead electrocardiogram (ECG) for all people — this may show a conduction abnormality, prolonged or short QT interval, bradycardia, ventricular or atrial arrhythmia.
• Consider arranging additional investigations, depending on clinical judgement and local service provision.
  • Blood tests — such as full blood count for anaemia. See the CKS topics on Anaemia - iron deficiency and Anaemia - B12 and folate deficiency for more information.
  • 24-hour ambulatory blood pressure monitoring (ABPM) with a diary of activities — to assess for post-prandial hypotension, exercise-induced and drug-induced hypotension, supine hypertension, and the degree of OH if suspected, for example.
  • Echocardiogram — if there is previous known coronary heart disease, suspected structural heart disease, or suspected syncope due to a cardiac cause.
• Consider asking the person/carer to make a video recording of any future spontaneous event(s), particularly if the diagnosis is unclear or history-taking is difficult.
  • If there is any uncertainty after initial assessment as to whether episodes represent a blackout or syncope, it should be assumed that these episodes are blackouts or syncope until proven otherwise.

What else might it be?

Other conditions which may present similarly to a blackout or syncope, but without loss of consciousness, include:

• Falls — if no unresponsiveness or amnesia. See the CKS topics on Falls - risk assessment for more information.
• Epilepsy — complex partial seizures or absence seizures where a person remains actively upright (sitting or standing). See the CKS topic on Epilepsy for more information.
• Psychogenic pseudosyncope (PPS) — characterized by loss of muscle tone with the appearance of syncope; duration of apparent loss of consciousness lasting minutes to hours; high frequency, up to several times a day; movements are absent; more likely if eye closure, resisted eye-opening, partial responsiveness during the event.
• Psychogenic non-epileptic seizures (PNES) — frequent, recurrent episodes often with a long duration of apparent loss of consciousness, the nature of the events changes over time; often presents with dramatic limb movements and multiple unexplained physical symptoms such as altered sensation or experience, due to a psychological process.
• Cataplexy — falls with flaccid paralysis or paresis and non-responsive, but no loss of consciousness and no amnesia. Triggered by emotion, usually laughter.
• Intracerebral haemorrhage/stroke or transient ischaemic attack (TIA) — consciousness may be maintained or progressively reduced rather than suddenly lost. See the CKS topic on Stroke and TIA for more information.
• Metabolic disorders or intoxication — may include hypoglycaemia, hypoxia, hyperventilation with hypocapnia. Longer duration than transient loss of consciousness; consciousness may be impaired rather than lost. See the CKS topics on Diabetes - type 1 and Diabetes - type 2 for more information on the presentation and management of hypoglycaemia.
• Cardiac arrest — loss of consciousness but no spontaneous recovery. See the CKS topic on Cardiac arrest - out of hospital care for more information.
• Migraine — may be associated with syncope in some people. See the CKS topic on Migraine for more information.

Scenario: Management

From age 16 years onwards.

Search strategy

Scope of search

A literature search was conducted for guidelines and systematic reviews on primary care management of blackouts.

Search dates

November 2018 - January 2023

Key search terms

The terms listed below are the core search terms that were used for EBSCO MEDLINE (searched 5th November 2018). These terms were combined with search filters for systematic reviews and guidelines in EBSCO MEDLINE. The strategy was adapted for The Cochrane Library databases. 

S7 S1 OR S2 OR S3 OR S4 OR S5 OR S6
S6 AB ( TLOC or "T-LOC" ) OR TI ( TLOC or "T-LOC" ) 
S5 AB faint* OR TI faint* 
S4 AB ("loss of consciousness" N3 (transient or spontaneous or temporary or brief or short)) OR TI ("loss of consciousness" N3 (transient or spontaneous or temporary or brief or short)) 
S3 AB syncope OR TI syncope 
S2 AB ( blackout* or "black out*" ) OR TI ( blackout* or "black out*" )
S1 (MH "Syncope+") 

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.