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Kamal Mahtani's blog

Just a spoonful of sugar, to help the obesity epidemic go down

Kamal Mahtani
Last edited 19th October 2011

Teaching on an Evidence Based Practice workshop recently I came across a truly jaw-dropping projection. A participant used a clinical scenario about obesity to bring up a paper about the US Obesity epidemic.The study is three years old now, but the authors use data on adults and children from the National Health and Nutrition Examination Study (NHANES), between the 1970s and 2004. The projections are frightening for the burden and health-care costs of obesity and overweight in the US if current trends continue. By 2048, all American adults would become overweight or obese. Depending on your ethnic background it could even be worse with the authors stating that Black women and Mexican-American men are likely to reach that state even earlier. However, the authors point out that they make a number of assumptions. Firstly they assume that the increase in obesity will be at its current rate. They also ignore the effect that all future policy, environmental and behavioural changes may have. Finally they ignore the possibility that some individuals may be genetically protected from becoming obese.

In the UK the predictions are not that much better. A recent four part series on obesity in The Lancet journal included a paper co-authored by Professor Klim McPherson of The University of Oxford. Their study stated that by 2030 there would be an additional 11 million more obese adults in the UK. This would have a knock on effect of an extra 6-8 million cases of diabetes, 5—7 million cases of heart disease and stroke and approximately 600,000 additional cases of cancer. This sort of news travels fast with The Daily Mail being one of the first to report these finding to the public.

So is it all doom and gloom? Not necessarily. In the same paper the authors go on to suggest that a 1% reduction in BMI (equivalent to a 1kg loss) across the entire population could avoid up to 2 million incident cases of diabetes, nearly 2 million new cardiovascular disease cases, and 73 000–127 000 cases of cancer. The authors further infer that this could be achieved through a reduction of 20kcal/day sustained over 3 years i.e. less about a teaspoon of sugar a day. Better still, if we were all able to give up 200 to 400 kcal/day, obesity levels would drop to 1990 prevalence levels.

So small changes may be the best way to start beating this epidemic. Something to think about before adding that spoon of sugar to your next tea or coffee.

A Risky Business

Kamal Mahtani
Last edited 17th August 2011

A great deal of General Practice is essentially about managing risk. Every time a patient walks through your consulting door you are basically thinking “what are the chances of this patient coming to harm from what they are about to tell me?” Some patients will fall into a category of “high risk” needing immediate or quick treatment. Others may have a degree of risk that necessitates either further investigations or monitoring. Or there may be low risk cases which can be assessed, reassured or treated. This is all supposed to happen within 10 minutes.

But how far should we go to convey that risk to our patients and what is the best way to do it? A recent scenario at my practice made me pause for thought. The cardiologists had advised us to have a discussion with a patient on the merits and risks of aspirin versus warfarin for their atrial fibrillation.

How could that conversation go?

“Right Mr X, the cardiologists have written to me and asked me to help you decide between warfarin or aspirin. They mention in the letter that the risk of you now having a stroke is about 6% per year, however aspirin reduces that risk by about 25% but with warfarin there is about a 45% risk reduction. However, the number needed to treat with warfarin is 37, but bear in mind that warfarin increases the annual absolute risk of major haemorrhage by 2%, so it’s up to you, which one would you prefer? ”

“umm…I’m sorry Doctor, I didn’t understand all of that”

“No neither did I”

So how should we explain risk to patients? The 2002 BMJ clinical review “Explaining risks: turning numerical data into meaningful pictures” by Edwards and colleagues is certainly worth a read. More recently, a study in the Annals of Family Medicine also tried to answer the question. The group surveyed 934 consecutive patients drawn from family practitioners’ waiting rooms in Auckland, New Zealand. Patients were asked to rate how much various modes of communicating the benefits of therapy, to their 5-year CVD risk score, would encourage them to take medication daily. The modes offered to them included: relative risk, absolute risk, odds, number needed to treat, and natural frequencies. The same information was presented in 2 pictorial forms (bar graphs and 10 × 10 people charts). Most patients (61.8%) preferred a doctor to give an opinion than to explain using either numbers or pictures. More than half also preferred a pictorial presentation to numbers; and of the numerical presentations patients found relative risk reduction most encouraging, with absolute risk reduction rated second overall and numbers needed to treat (NNT) the least likely to be persuasive to take their medication.

So should this mean to our practice? Remember EBM is the integration of the best clinical practice, personal expertise and individual patient preference. The latter component is dependent upon the patient fully understanding the risks and benefits of treatment so that a shared management plan can be reached. Having an idea of what those risks mean ourselves is the first step but finding the best way to convey it to our individual patients in as simplest way as possible is perhaps the bigger challenge.

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