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Don’t let good intentions undermine population screening principles

Posted by: , Posted on: - Categories: UK National Screening Committee

Public Health England (PHE), the UK National Screening Committee (UK NSC) and the NHS Screening Programmes are recognised internationally as models of good practice.

It is therefore vital that all of us in the public health community do not accidentally damage that reputation when acting with the best intentions.

It is particularly important for colleagues working in PHE and NHS England to understand population screening and the rigorous criteria and processes that underpin our national programmes. Any initiatives to do something about common risk factors or disease must not undermine or overlap with population screening. That could result in contradictory policies, damaged reputation and a lot of work to undo the damage.

Illustration of weighing scales with a group of people in each side of the scale. This illustrates the balance of benefits and harms to the population as a whole that are weighed up when considering screening recommendations.
There must be evidence that benefits clearly outweigh harms for the population as a whole to justify screening

For example, we know many NHS colleagues will be as concerned as us about the effects of Group B Streptococcus in newborn babies. So some hospitals may be keen to offer testing to pregnant women. But if such testing is offered to all women regardless of risk factors or previous clinical history, this becomes population screening and is therefore for the UK NSC to make a recommendation on.

The UK NSC last did this in March 2017 and recommended against screening. Local initiatives, outside of carefully planned and evaluated pilot schemes, can be a ‘back door’ to screening, without the national standards, training, data collection and quality assurance that the UK NSC-recommended programmes have.

It may also seem obvious to add a test for atrial fibrillation to routine contacts with middle aged and older adults because early treatment can lead to better health outcomes. Unfortunately, screening is indiscriminate and picks up all sorts of other problems, such as unknown heart rhythms, that would never make the person ill. Once discovered they can set an individual off on a journey from being a well person to being sick, which means more tests, more worry, pills and treatments which they never needed.

It is because so many well people are involved that there is international agreement that the benefits of helping a person with early disease must be balanced against the certainty of harming and frightening thousands of well people. Ideally, this balance should be studied through proper randomised population screening trials. Screening must be based on high quality evidence of its overall benefit to the population. It must not be introduced based on the anecdotal opinions of individual clinicans, managers and policy makers. Additionally, introducing new tests can also divert huge amounts of money from diagnosis and care to testing millions of well people and taking money from interventions such as smoking cessation, or exercise on prescription.

So, if you are thinking of testing or applying a questionnaire to a whole population – such as all pregnant women, all newborn children or all individuals within a certain age range – then please exercise caution. Stop and speak to the PHE Screening team first.

Why screening is different

NHS screening programmes are based on internationally recognised criteria and a rigorous evidence review process. Our 11 national programmes each year enable millions of people to make informed decisions about their health, helping thousands to live longer lives.

Screening policy has a particular place in the NHS Constitution and screening programmes differ from other national programmes, campaigns or advice to people to adopt or change behaviours. Unlike screening, campaigns such as One You and Stoptober do not write to people in their homes offering an appointment for a test or treatment.

Clinical guidance, such as those for atrial fibrillation in people on hypertension registers, provides tests and treatment to people who know they are at risk or are currently unwell. They are also done in the context of a face-to-face clinical discussion and are the responsibility of the National Institute for Health and Care Excellence (NICE) and the Royal Colleges.

In contrast, screening programmes write and offer tests to well people in their own homes on NHS-headed paper, and sometimes with their own GP’s name. PHE provides expertise on all aspects of health screening, advising the government and NHS so England has safe, high quality screening programmes that reflect the best available evidence and the UK NSC recommendations.

Screening is not perfect and is only recommended if strict criteria are met so that it does more good than harm at a population level. It is therefore important that population screening is implemented consistently throughout England. Small problems and variations in implementation can have a large impact and unintended consequences.

So, if you are thinking about implementing a health initiative, please consider its possible impact on screening. If any doubt, talk to the PHE Screening team first. We’re always here to help. And if you have suggestions for new types of screening, you can submit these to the UK NSC.

PHE Screening blogs

PHE Screening blogs provide up to date news from all NHS screening programmes. You can register to receive updates direct to your inbox, so there’s no need to keep checking for new blogs. If you have any questions about this blog article, or about population screening in England, please contact the PHE screening helpdesk.

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