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November 2010

Variation and inequality-what are the causes?

Ami Banerjee
Last edited 26th November 2010

Yesterday the NHS Atlas of Variation in Healthcare was launched. It aims to “address variations in activity and spend within the NHS” and “search for un-warranted variation”. Unwarranted variation is defined as “Variation in the utilization of health care services that cannot be explained by variation in patient or patient preferences”, and addressing it may “maximise health outcome and minimise inequalities”. The media coverage, as expected, has focused on the shocking “postcode lottery” of NHS healthcare with a 14-fold difference in hip replacement rates and a three- to four-fold variation in the percentage of patients getting the best possible stroke care. Across countries and across disease areas, there has been a flurry of research to show both VARIATION and INEQUALITIES. What do these words mean?

Variation, variability and statistical dispersion are terms often used interchangeably, but they all describe the spread of a variable. Variation can be described using measures such as the standard deviation, the range and the coefficient of variation (CV). For example, the CV is defined as the ratio of the standard deviation to the mean. CV, unlike the standard deviation or the range, does not have units-ie. It is dimensionless.

Variability can occur due to random measurement errors. For example if we assume the outdoor temperature to be fixed, the variation between measurements is due to observational error. With people, such assumptions are false: observed variation is because distinct members of a population differ greatly. For example, the way we measure blood pressure has been called into question by recent research about blood pressure variability

The Longman’s dictionary defines “inequality” as “an unfair situation, in which some groups in society have more money, opportunities, power etc than others”. So “inequalities” are “unwarranted variation”. Probably the most famous recent studies of health inequalities are Sir Michael Marmot’s Whitehall Studies, first started in 1967, showing that men in the lowest employment grades in the civil service were much more likely to die prematurely than men in the highest grades, and led to the study of “socioeconomic inequalities in health”. The WHO set up a Commission for Social Determinants of Health, led by Marmot, which has published several reports on how to address social health inequalities. Another example of health inequalities research is the Global Burden of Disease project of the WHO has studied variations and inequalities in global disease distribution.

But the difficult part is characterising what causes these variations. The Right Care programme, led by Sir Muir Gray, has for the first time attempted to aggregate what the NHS spends on particular groups of disease. Perhaps surprisingly, this list is topped by more than £10bn spent on mental health in England, £7.5bn on circulatory diseases, and £5bn on cancers. The unpacking of this kind of data is where the real inequalities will get tackled.

Why Kings shouldn’t mess with clinical trials

Carl Heneghan
Last edited 14th September 2012

The best teaching scenarios often come from other teachers or their presentations. The King Gustav example and why Kings shouldn’t mess with clinical trials is a great example of this. I pinched this off, C. Wanner I have no idea who he is, but thanks, I’m using it again in the morning as an opener and thought I’d share it with a wider audience.

An early Clinical Trial
In the late 18th century, King Gustav III of Sweden decided that coffee was poison and ordered a clinical trial.
J Int Med, October 1991:289, Reprinted in Ann Intern Med 1992;117:30

Study design
- The king condemned a convicted
murderer to drink coffee every day.
- Control: another murderer was
condemned to drink tea daily.
- Outcome: death.
- Two physicians were appointed to
determine the outcome.

Results
- The two doctors died first.
- The king was murdered.
- Both convicts enjoyed long life until the
tea drinker died at age 83 (no age was given for the coffee drinker).

Discussion
One should not rely on such a small sample size. Perhaps the end point was too harsh.
The outcome of the trial had no effect on the decision makers. Coffee was forbidden in Sweden in 1794 and again in 1822.

Conclusions
None possible.
External events and other biases may have confounded the result.
Kings should not mess with clinical trials.

Mobile phones and healthcare improvement

Ami Banerjee
Last edited 11th November 2010

I remember as a medical student how averse to mobile phones the hospital environment was, particularly around patients on cardiac monitors, and even in hospital corridors. Thankfully, most hospitals are more sensible in their approach these days; allowing relatives and patients to use their phones in most hospital areas at a time when communication is very important to them.

Most of the fear around health risks posed by mobile phones has focussed on cancer. A major review of existing studies showed that mobile phone use led to “no increased risk within approximately 10 years of use for any tumor of the brain or any other head tumor”. This data is particularly strong for fast-growing tumors (e.g. malignant glioma). On the other hand, for slow-growing tumors (e.g. meningioma and acoustic neuroma), the observation periods of mobile phone use within studies have been too short. Similarly, a case-control study published this year in the BMJ showed no association between risk of early childhood cancers and maternal exposure to mobile phone base stations during pregnancy.

It turns out that mobile phones are of great interest to medical researchers: 2602 hits in Pubmed to-date with 160 review articles. For over 10 years, the potential of telemedicine and mobile phones as a force for good in healthcare has been explored. The benefits of mobile phone usage in disease management programmes have been found across many diseases, from reducing frequency and duration of heart failure hospitalisations and self-monitoring of glucose in diabetes to obesity and hypertension.

A systematic review titled, “Healthcare via cell phones identified 25 studies that evaluated cell phone voice and text messaging interventions, with 20 randomized controlled trials and 5 controlled studies. “Frequency of message delivery ranged from 5 times per day for diabetes and smoking cessation support to once a week for advice on how to overcome barriers and maintain regular physical activity. Significant improvements were noted in compliance with medicine taking, asthma symptoms, HbA1C, stress levels, smoking quit rates, and self-efficacy, …….with implications for both patients and providers.”

As bluetooth technology improves to allow remote assessment of patients, particularly in blood pressure monitoring, it seems that mobile phones may represent one of those rare technological advances that can also be useful in low resource settings. The Lancet Online published the results of a randomised controlled trial from Kenya today showing that mobile phone communication between health-care workers and patients starting antiretroviral therapy improves adherence to therapy. 538 clinic patients starting antiretrovirals were randomised to either receive weekly SMS messages from a clinic nurse or to standard care with impressive NNTs. To achieve greater than 95% adherence, only 9 patients needed to receive SMS messages, and to achieve suppression of the viral load of HIV only 11 patients needed to get SMS reminders. The (SMS) message is very clear. Health professionals have to stay afloat of technology and use all available tools to improve healthcare outcomes, maybe even more so in resource-poor settings.

Shocking maths at the BBC - why most research findings are false

Carl Heneghan
Last edited 4th November 2010

Some studies suggest people have trouble with maths. I am having trouble understanding what Fergus Walsh as the BBC health correspondent tonight is doing reporting this stuff as major BBC news .

The study authors, quote ‘Applying a tiny electrical current to the brain could make you better at learning maths, according to Oxford University scientists.’ They ‘found that targeting a part of the brain called the parietal lobe improved the ability of volunteers to solve numerical problems.

They hope the discovery, reported in the journal Current Biology, could help people with dyscalculia, who may struggle with numbers.

Thank God they aren’t advising you to go round giving yourself shocks ‘We are not advising people to go around giving themselves electric shocks” I was thinking of wiring myself up to my bike lights and seeing if it improved my understanding of logistic regression. Oh well.

The study Modulating Neuronal Activity Changes
in Numerical Competence
concludes:

TDCS is a realistic tool for intervention in cases of atypical numerical development or loss of numerical abilities because of stroke or degenerative illnesses.

I have no idea how they drew the conclusion with stroke patients. The maths that gives me an electric shock is the sample size: over 6 days, 15 healthy adults learned the association between nine arbitrary symbols.

Most of you, who read this column, will by now no the sample is so small it renders the results impossible to interpret.

This is what Ionaddis says on the issue in Why Most Published Research Findings Are False

The smaller the studies conducted in a scientific field, the less likely the research findings are to be true. Small sample size means smaller power and, for all functions above, the PPV for a true research finding decreases as power decreases towards 1 − β = 0.05. Thus, other factors being equal, research findings are more likely true in scientific fields that undertake large studies, such as randomized controlled trials in cardiology (several thousand subjects randomized) than in scientific fields with small studies, such as most research of molecular predictors (sample sizes 100-fold smaller)

It would be helpful if this sort of stuff was understood by organizations such as the BBC. Looks to me, a bit of evidence based science training wouldn’t go a miss. Maybe a bit of shock therapy would also help: better bring the bike lights then.

Evidence 2010-Transforming healthcare. Afternoon thoughts

Ami Banerjee
Last edited 1st November 2010

After a hearty lunch, I attended the breakout session about the role of medical journals in raising awareness of evidence. Bill Summerskill, Executive Editor of the Lancet, helpfully described “research” as the roots, “evidence” as the tree and “evidence-based practice” as the fruits which take much more time and effort to produce. He described the measures that the Lancet currently uses to publish the right research with the maximal effect. The problem of plagiarism, setting the research agenda and the importance of targeting readers were just some of the issues raised. We often think of the publication of research in journals as the starting point for media articles, but one of the listeners tackled was the possibility of journals moving in the other direction and taking responsibility for publishing research in the face of media hype.

Sir Ian Chalmers, founder of the Cochrane Collaboration and coordinator of the James Lind Initiative, eloquently described the mismatch between research funding and disease burden. He quoted the “profit motive” (money is in diseases and problems which are different to the major burden of disease), “reductionist snobbery” (the medical community perversely rewards study of clinically small problems) and “criteria for academic recognition” (problems in current culture in research institutions) as major reasons for this mismatch. Amazingly, 60% of research findings presented in conferences never get published, often because they are never submitted to journals. And this is even though so much research funding comes from public sources. Chalmers gave the example of use of steroids after traumatic brain injury as a common medical practice which was totally discredited by proper systematic review, but is sadly, still going on. He concluded that there are many good ethical reasons for getting rid of waste in research funding at the question-forming stage, the design stage, the publication stage and the report stage because research is to improve outcomes for patients at the end of the day.

After an awards ceremony for the best evidence poster, a panel discussion about the future of medical publication ensued. The panel consisted of Carl Heneghan, Director of the CEBM, Fiona Godlee, BMJ editor, David Tovey, Editor in Chief of The Cochrane Library, and Bill Summerskill, Lancet Executive Editor. Carl spoke of the roles of individuals in pushing forward the quality and relevance of research, and conflict of interest remained a significant hurdle. Fiona Godlee spoke of the “broken state” of medical publishing of evidence, which needed a “great deal of scrutiny”. She acknowledged vested interests and conflicts of interests throughout the whole research structure which required total openness. Greater transparency, open access and improvement of patient outcomes have to be primary aims of medical publications. Bill Summerskill said the mechanism of production of the Lancet and other journals has changed beyond recognition in the last 30 years, but the overall aim of quality and peer review remains the same. He believes that technology and globalisation to be major drivers, with Asia, and China in particular, leading in the generation of research evidence. The public will be interested in “social value” rather than impact factor of journals, and so the journal “Nothing is more tarnished than yesterday’s vision of today.” David Tovey had “grounds for cautious optimism”, even though he was sure the paper copy and medical journals in their current form were dead.

Tom Jefferson, of the Cochrane Collaboration, posed the question "What can journals do to improve the reporting of trials?" Bill Summerskill felt that trial registration is only one part of the solution of finding all available data about drugs and interventions. Carl agreed and went further, saying that there had to be more mandatory reporting of trials within a given timeframe; registering trials is not enough. The challenges of EBM in the US and of evidence informing policy dominated the discussion, with calls for research to be put in online databases rather in journals and greater collaboration. The second day will hopefully talk as much about the potential solutions as the problems facing medical evidence.

Evidence 2010-Transforming healthcare. Morning thoughts

Ami Banerjee
Last edited 1st November 2010

Even as I was coming up down to London on the train from Birmingham, medical evidence was all over the news, with "alcohol more harmful than heroin". Evidence about healthcare is of interest to all sectors of society but we don't often get everybody in one room talking about it. For 2 days at BMA House in London, health professionals, researchers, information scientists and policymakers from all over the world are debating the what, where, how and why of evidence in healthcare in the first conference of its kind. Evidence 2010 is jointly organised by the CEBM and the British Medical Journal.

After Fiona Godlee, BMJ Editor, had welcomed the international audience, Carl Heneghan, Director of the CEBM, referred to "I don't know" as the three most important words we were not taught at medical school, in his opening remarks. Jim Easton, NHS Director of Improvement and Efficiency, described cost as an ethical consideration which every healthcare system was facing in the current financial climate. The difficulty is matching increased quality with cost reduction, he noted, and this is going to be the holy grail across all healthcare systems.Customers and consumers are taken into account much more in other industries outside of healthcare, and this culture to include patients has yet to permeate the NHS. Easton called for a "hybrid vigour" across healthcare, policymakers and patients to move policy and evidence in the right direction. Sir Muir Gray, Chief Knowledge Officer of the NHS, reminded us that "irritation" and "stimulation" had been key drivers for change in healthcare, the former often more successful than the latter. He called for a change in culture and in the language of evidence-based healthcare.

In a breakout session about evidence-based policy. Dan Lasserson from Oxford, spoke of the exponential rise in Medline citations in policy documents in the UK in the last 2 decades. but in the end, warned that "values will always be more influential than evidence". Before lunch, Tim Wilson, a healthcare consultant, spoke of the challenge of complexity in translation of evidence into policy. Plenty of food for thought and more to come in the afternoon....

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