Health for life

Migraine headaches are a major cause of ill health and a reduced quality of life. Some individuals suffer from a frequent and severe migraine problem which means that they require regular medication to try and prevent them. A new review_ of the medications, which may help to prevent episodic migraines, appears in the Journal of General Internal Medicine_, published by Springer. The authors, Tatyana Shamliyan from the University of Minnesota School of Public Health, and her colleagues, compare published research on the drugs available to find those which offer the best migraine prevention coupled with the fewest adverse side-effects.


Preventive treatments for migraines aim to reduce the number of migraines suffered by fifty percent. There are a number of different drugs commonly used, all of which may cause some side effects. The researchers carried out a review of studies which tested how well the different types of drugs worked and also their acceptability in terms of adverse effects suffered. The studies used enrolled mostly middle aged women with episodic migraine who suffered an average of five monthly migraine attacks.


The authors found that all approved drugs used in the reviewed trials worked better than placebo in reducing monthly migraine attacks. They all demonstrated similar effects in that they prevented half or more migraines in 200 to 400 patients per 1000 treated. Off-label anti-epilpetics and anti-depressants appeared to cause the most bothersome side effects which usually resulted in the medication being stopped. Off-label beta-blockers and angiotensin-inhibiting drugs caused the fewest side-effects. (Off-label drugs are drugs which have not been approved by the Food and Drug Administration for a specific condition).


The American Academy of Neurology and the American Headache Society currently recommend two types of anti-epileptic drug and two beta-blockers for adult migraine prevention. These guidelines do not consider the balance between the effectiveness and harms of the drugs they recommend. As well as the increased occasion of immediate side effects with anti-epileptics, there is also evidence from other studies that with long-term use they can cause sexual problems such as impotence which would also deter long-term adherence.


Shamliyan and her colleagues suggest that future studies should examine the effects of the approved as well as the off-label drugs, taking into consideration patient demographics, family history of migraine, other illnesses and response to prior treatments. They also suggest that vigilance should be increased to monitor any adverse effects of current migraine-preventing drugs. Only once the necessary evidence is available, will migraine sufferers be given the best possible hope of a better quality of life with a preventive treatment that is more pro than con.

Michael Baum, Professor emeritus of surgery at University College London says that, while deaths from breast cancer may be avoided, any benefit will be more than outweighed by deaths due to the long term adverse effects of treatment.

He estimates that, for every 10, 000 women invited for screening, three to four breast cancer deaths are avoided at the cost of 2.72 to 9.25 deaths from the long term toxicity of radiotherapy.

These figures contrast with an independent report on breast cancer screening, led by Sir Michael Marmot and published in November last year. Marmot and his committee were charged with asking whether the screening programme should continue, and if so, what women should be told about the risks of overdiagnosis.

They concluded that screening should continue because it prevented 43 deaths from breast cancer for every 10,000 women invited for screening.

The downside was an estimated 19% rate of overdiagnosis: 129 of the 681 cancers detected in those 10,000 women would have done them no harm during their lifetime. However, those women would have undergone unnecessary treatment, including surgery, radiotherapy and chemotherapy.

But despite this higher than previous estimate of overdiagnosis, they concluded that the breast screening programme should continue.

The report also judged that screening reduces the risk of dying from breast cancer by 20%. But Professor Baum disputes these figures, saying the analysis takes no account of improvements in treatment since these trials were done, which will reduce the benefits of screening. Nor does it make use of more recent observational data.

With these data included, estimated rates of overdiagnosis as a result of screening increase to up to 50%, he argues.

This is important because it can change the decisions women make when invited for screening. In a study also published today, researchers at the University of Sydney explored attitudes to screening in a sample of 50 women. Many of the women were surprised when they were told about overdiagnosis and most said they would attend screening if overdiagnosis rates were 30% or lower, but a rate of 50% made most of them reconsider.

An accompanying editorial points out that the harms of screening will reduce as more effective diagnostic processes develop to inform less harmful and more personalised treatments. In the meantime, it says women need up to date and transparent information about the benefits and harms of screening to help them make informed choices.