Over recent years, there’s been an increase in magazine advertising and direct mailing to the public about tests to screen for a range of diseases. Assuming you can afford these tests, should you go for them? Is this advertising helping people to control their own health or is it simply exploiting deep-seated fears?

It’s true that early detection of a disease often offers the best chance for effective treatment. Cervical cancer provides a good example: detecting the earliest signs of the cancer itself – or of its precursor – has saved many lives. But screening for diseases can raise some tricky issues.

Even with cervical cancer – for which there is good epidemiological data and wide agreement over diagnosis and treatment – not everything is as straightforward as you might expect. For example, there are differences between the four UK countries about the age at which screening should start.

The complexity of screening more generally is illustrated by some major questions about the value of mammography screening for breast cancer, where ‘false positive’ results can cause unnecessary distress for women. There are also doubts about using the blood test PSA in screening for prostate cancer – and, indeed, in the best way to treat this cancer if detected. There’s no point in detecting a condition if it’s uncertain what should be done about it.

A range of other conditions can be screened for and it’s likely the range of tests will continue to expand. For example, checking blood glucose levels can reveal type 2 diabetes, and checking cholesterol levels may show a liability to heart disease. Lifestyle advice and, where appropriate, medication can then significantly reduce the risk of the disease; but even with these there is continuing debate. For something like an ultrasound scan of the carotid arteries in the neck, which is now available, it is far from established that there are benefits for the patient if an abnormality is discovered.

Within the NHS there is a process, aided by independent authorities, for evaluating such tests and giving the best guidance on their use. To establish the usefulness of a screening programme takes detailed scientific work extending over several years. Even then, doubts can arise.

Scans – such as CT, MRI and ultrasound – are now widely used in clinical practice where they have revolutionised diagnosis in a way that was unimaginable 50 years ago. These work best when the clinician has an idea of what’s being looked for. For example, using CT to scan smokers for lung cancer has been shown to detect early cancer and there’s some evidence it improves the outcome for the patient.

But it’s probably not worth investing in a whole-body scan – as is now available at a price – especially if you have no symptoms of disease. No one has shown any clear overall benefit for this. Indeed, it would take a very large study of several years duration to establish efficacy, and this hasn’t been done. It’s worth noting that CT scanning exposes the body to significant irradiation and, if repeated, the cumulative dosage can rise to a dangerous level. MRI scanning is often unpleasant for those with claustrophobia.

More important, though, is the question of what you might want to do with an unexpected finding? Do you seek out further tests or proceed to treatment? The cascade of further investigations may not be without hazard, and there is the fear and uncertainty even when nothing abnormal is found in the end.

There is also an issue with scans that don’t show any problems. This is not the same as proving the scanned person is free from all disease, but it can potentially lead to them believing they are and ignoring symptoms they might otherwise have told their doctor about.

Normally a scan or test is planned with a medical adviser who can explain it, why it’s being done and what is proposed if it turns out abnormal. Doing tests blindly is different. Purveyors of directly marketed tests talk about referring on to another practitioner without clear indication of who this might be. Many of them will do no more than send results to your usual doctor.

Some people are bound to benefit occasionally from tests such as these bringing something to light, but overall is it worth paying to have these tests if you don’t have any symptoms? Probably not. Even in the United States, with their very different medical care system, doubts have been expressed about the sense of these commercially provided tests. In the UK your money would be better spent elsewhere.

If you have symptoms then it’s best to talk to your doctor about them. He or she can then arrange investigation through the NHS – or privately – with the advantage that there will be someone who can interpret for you what any findings mean and can arrange whatever further care or observation you might need.

 

Link to a discussion of the ethics of commercial screening tests:  http://annals.org/article.aspx?articleid=1355172

 

High blood pressure is common. Left untreated, it contributes to stroke, coronary heart disease and heart failure. We therefore recommend you should get your blood pressure checked regularly. Diagnosis is quite easy and there are effective medicines to treat it.

Unfortunately, though, these can occasionally lower blood pressure too far. For younger patients, the consequence of this is that they feel faint at times, but it usually corrects quickly. Reducing the dose stops any recurrence, and this is no reason to miss out on potentially life-prolonging treatment.

But it’s not so straightforward for the elderly. They are not able to compensate so quickly for a drop in blood pressure, and the resulting unsteadiness can cause them to fall and potentially injure themselves. In addition, a critical pressure must be maintained to ensure sufficient blood flow to their brain. This is the reason it takes longer to stabilise an elderly patient on blood pressure lowering medication.

Studies show there are benefits for treating blood pressure in the elderly – but there are some nagging doubts. How do you ensure the right people are treated, especially given that there are general practice incentives in the NHS for doing so?

A recent commentary and a scientific review have raised questions about balancing the risks against the advantages of lowering blood pressure in the elderly. Dr Spence, writing in the British Medical Journal*, asks whether too many elderly patients are being put at unnecessary risk by an enthusiasm for meeting a numerical target rather than assessing all aspects of the patient. If a person is frail, ill with another condition and likely to die soon, what’s the point of ineffective treatment that carries a risk? On the other hand, someone in more robust health might benefit significantly from life-prolonging blood pressure treatment.

Many people would go along with this idea, but it’s difficult to know how to make an assessment of a patient’s frailty. It cannot simply be a matter of age. There are 80-year-olds who are active – sometimes more active than younger people – and others whose quality of life is impaired.

Recent research** has provided some help in assessing frailty through a straightforward test of walking speed. The researchers measured walking speed in 2340 patients with high blood pressure aged over 75 years. After ruling out other factors that might have interfered with walking speed, they divided the patients into those that walked faster than 0.8 meters/second (about 75 feet in 30 seconds) and those that were slower than this. Over a seven-year follow-up period, there were 24 deaths per thousand person years in the fast walkers but 70 deaths per thousand person years in the slow walkers. This suggests a way to pick out the fitter people who are more likely to benefit from life-prolonging preventive treatment.

These observations don’t fully answer every question about treating elderly people with high blood pressure and there may be other more pertinent measurements. But they do make a start in differentiating people who are frailer and therefore less likely to derive benefit from treatment.

If you are elderly and are diagnosed with high blood pressure, make sure you discuss fully all the pros and cons of treatment with your doctor before coming to an informed decision about the best option for you personally.

 

Link to the British Medical Journal commentary: http://www.bmj.com/content/345/bmj.e5923

Link to the research paper: http://dx.doi.org/10.1001/archinternmed.2012.2555

 

 

It seems that increasing numbers of men and women are getting tattoos these days. Overall, the risks from tattoos of infection, allergy and unwanted skin reaction are low – this has been known for decades. Recently, though, there have been reports from the United States of an infection transmitted by a grey ink used in tattooing.

Although the initial outbreak only affected 19 people, the bacterium responsible – Mycobacterium chelonae – comes from a group that’s difficult to treat. Another eight infections with this and a related bacterium were then reported in other states. These were from tattoo ink made by other companies. The US Center for Disease Control and Prevention investigated more widely and turned up other suspected cases. A review of the quality of inks showed that about 10% of them were contaminated with bacteria.

In the UK, tattoo studios are governed by national and local bye-laws to ensure the premises are suitable and hygienic, with measures in place to prevent the spread of infection and to conform to health and safety requirements. Although there is no formal training requirement, many authorities seek to check the proprietors have the right skills. There are UK laws regulating tattooing minors.

The overall risks of getting a tattoo are still not great, but these findings should be considered carefully by anyone wanting one.

For regulators, there is the continuing question about ensuring the safety of cosmetics, which are not scrutinised as thoroughly as medicines.

 

Link to findings on tattoo ink: http://www.nejm.org/medical-research/public-health

N Engl J Med 2012; 367:1020-1024 September 13, 2012

 

Professor Brian Kirby, Co-author of How to Live to 110: Your comprehensive guide to a healthy life

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