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In this series a GP interviews an expert to get first-hand information that goes beyond the textbook on a topic of current clinical interest

GP Dr Roger Henderson asks National Obesity Forum president Dr Ian Campbell about how to manage obese patients

Practical points

 · The number of cancer-related deaths in obese patients is 55 per cent higher than in non-obese patients

 · Basal metabolic measurements and hormonal investigations are useful tools when making the case to patients that there is no medical reason why they cannot lose weight

 · Drug treatments are increasingly being recognised as having a key role in sustaining weight loss

 · Surgery is recommended by NICE as a cost-effective solution for morbidly obese patients when diet, lifestyle advice and pharmacological interventions have been unsuccessful

 · A small amount of weight loss can have a dramatic effect in reducing the patient's risk of obesity-related co-morbidities

How worrying is obesity in the UK?

How worrying a problem is obesity in the UK? Is it hype?

Well, it's certainly not hype! Over the past 20 years obesity in the UK has reached epidemic proportions and, more worryingly, its rapidly accelerating incidence shows no sign of receding. Estimates suggest that by 2010 as many as 30 per cent of adults will satisfy clinically obese criteria.

To put things into perspective, in 1980 only

7 per cent of UK adults were reported as obese, yet by 2000 this prevalence had risen to 21 per cent.

Childhood obesity raises similar concerns as the prevalence of overweight children has doubled in the past 10 years, and around one in three 15-year-olds are now overweight. Serious figures.

So what are the health concerns linked to this?

Each year an estimated 30,000 deaths are directly attributed to obesity. And its co-morbidity significantly increases the likelihood that a patient will not only contract a medical condition ­ but that the condition will prove fatal. The main conditions here are ischaemic heart disease, congestive heart failure, hypertension, type 2 diabetes, depression and various cancers such as colon, rectum, prostate, breast, ovarian, stomach, or oesophagus.

Another important point here is that when compared with people within a normal, healthy weight range, the number of cancer-related deaths in obese patients is 55 per cent higher. Obese patients are also four times more likely to contract and twice as likely to die from coronary heart disease, and are 23 per cent more likely to commit suicide.

This must be an enormous expense for the NHS?

Correct. The health select committee that has looked at this problem estimates the costs of obesity to be from £3.3-£3.7 billion per year ­ a 42 per cent increase on previous estimates. If we include overweight into these figures they rise to £6.6-£7.4 billion per year.

What is the GP's role in obesity?

What do you see as being the role of the primary care practitioner in obesity?

In my view, GPs are ideally placed to manage obesity. This is because they are able to actively identify obese patients, provide dietetic advice and encourage and support them during weight loss and maintenance. In addition, they can manage any co-morbidities, provide additional weight management services such as obesity clinics, and refer to secondary care experts such as dietitians and endocrinologists.

Which all takes time ­ a commodity that I and my colleagues are preciously short of at the moment

I do realise that in some quarters there is a perception that GPs are too busy to manage obesity. Ironically it is the co-morbid repercussions of obesity, such as type 2 diabetes, hypertension and depression, that account for a significant proportion of our workload. The solution is therefore straightforward: taking time to treat obesity will help reduce the time spent on managing obesity-related co-morbid complications in the future.

However, for some patients, primary care management will not suffice. Secondary care referral can offer more detailed investigations such as assessment of basal metabolic rate, specialist nutritional advice, and comprehensive management of any pre-existing co-morbid conditions.

What treatment options should GPs be looking at then?

Well, diet and lifestyle advice is the obvious mainstay of first-line obesity management including a focus on the behavioural aspects of eating and physical activity. Patients should increase their daily exercise regimes, aiming for 30 minutes of scheduled exercise, five days per week. Usually, a patient should aim to lose up to 1kg per week, which on average requires a reduction in calorific intake of 500 kcal per day. An initial total weight loss of 5-10 per cent is a sensible, achievable target.

For many patients who successfully lose weight, a weight maintenance phase or period of stability may be undertaken before any further weight loss is attempted. This will require a continued restriction in energy intake, but more importantly patients will need to increase activity and exercise (a target of half an hour each day is desirable). This does not have to comprise a strenuous exercise regimen as walking briskly will often suffice.

What are the secondary care options?

What could secondary care offer?

For those patients with a BMI greater than 35, or in whom control of co-morbid disease is a problem, secondary specialist clinics can offer more intense investigation, expert dietetic advice, specialist medical involvement and access to added support from psychologists and bariatric surgeons.

There are, however, only 10 specialist centres throughout the UK and many are no longer accepting new referrals. Measuring basal metabolic rate, hormonal investigations and rarely genetic assessment is often useful in reassuring patients there is no medical reason why they cannot attempt to lose weight and be successful.

Where do drugs come into the equation ­ many of my obese patients are asking for these more and more

In 2001 NICE recommended that drug therapy should be considered for patients with a BMI >27 with co-morbidities, or BMI over 30. In most cases this is offered as an adjunct to lifestyle-based therapies and the two drugs commonly used for the long-term treatment of obesity here are sibutramine and orlistat . In my experience, within general practice, using sibutramine or orlistat helps achieve a >5 per cent weight loss in two-thirds of my patients and a >10 per cent loss in 25 per cent of patients over a one-year period. Since the publication of the NICE recommendation, a five-year sibutramine study is under way and four-year data has been published on orlistat.

Data currently available is impressive, producing significantly increased levels of sustained weight loss compared with lifestyle advice alone. It is therefore possible that the prescription timeframe of the NICE guidance will be extended. This is to be welcomed, as although the ideal scenario is for patients to eradicate poor dietary habits and revert to a healthier lifestyle, long-term compliance can be extremely problematic.

After cessation of drug treatment some patients can maintain their weight loss long-term but many do gradually regain over a two-year period. Because of the health benefits of maintained weight loss we are increasingly considering the role of drugs in weight maintenance. We wouldn't expect a diabetic to stop their hypoglycaemic medication after 12 months and for them to have completely redefined their lifestyle would we? So why do we expect just that of obese patients? Used properly, pharmacological agents can help patients maintain satisfactory weight control.

Is this very expensive?

Interestingly, despite the high cost of obesity to the NHS, relatively small sums are spent on obesity medications. This serves to highlight the widespread inadequacies associated with current obesity management, indicating that the vast majority of money is spent on co-morbidity management rather than prevention or early treatment.

Can we turn to surgery? This is again something patients ask me about but I steer them away from this wherever possible

I think that's correct. Laparoscopic surgery is generally regarded as a last resort and is only considered when a patient's obesity is life-threatening and their BMI is above 40 (or 35 with co-morbidities).

Modern techniques are effective, with a small (0.5 per cent) mortality risk. Successful surgery can yield a 50 per cent loss of excess weight within two years and is recommended by NICE as a cost-effective solution for morbidly obese patients when diet, lifestyle advice, and pharmacological interventions have been unsuccessful.

Despite its dramatic results, surgery should not be perceived as an easy option. For example, post-surgical patients are unable to eat 'normal' size meals for several years ­ a measure which could have significant repercussions on their social lives.

Does it merit primary care intervention?

What about the common misconception that obesity is simply a lifestyle disease that doesn't merit primary care intervention?

As existing data shows, obesity is associated with a number of life-threatening co-morbid conditions. Moreover, when a patient becomes obese it may reveal the existence of underlying, deep-rooted psychological problems. For these reasons, obesity is classified by the World Health Organisation as a chronic disease with serious health risks and should therefore be treated as such.

So can a small amount of weight loss actually have a significant impact on a person's health and obesity-related co-morbidities?

Yes absolutely. Even a small amount of weight loss, 5-10 per cent of a patient's overall body weight, can help reduce cardiovascular mortality by 9 per cent. Data presented at the recent European Congress of Obesity meeting showed sibutramine therapy results in a 10 per cent relative risk reduction in coronary heart disease over a 10-year period and the Xendos study (Xenical in the prevention of diabetes in obese subjects) showed that the risk of developing type 2 diabetes was 37 per cent lower in people treated with orlistat plus diet and lifestyle intervention versus diet and lifestyle intervention alone.

Is a low metabolic rate a significant factor in preventing satisfactory weight loss?

Although a person's metabolic rate has some bearing on his/her energy balance, virtually all patients managed within primary care will have a rate that is substantially higher than the minimum rate required for an effective weight-loss programme. This measure is of little relevance within the confines of GP practice.

Finally, what about the older patient who says they are too set in their ways to lose weight?

Older patients benefit greatly from modest weight loss and can report significantly enhanced quality of life with weight reductions of only 5 per cent. The key aspect for changing habits is motivation. Each member of the extended primary care team can help keep patients motivated with educational materials and active encouragement.

Roger Henderson is a GP in Newport, Shropshire

Ian Campbell is president of the National Obesity Forum and a GP in Nottingham ­ he is an associate specialist in the overweight clinic at The University Hospital, Nottingham

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