Obesity in Adults

A person is considered to be obese if he is so heavy that weight endangers health.¹ Obesity is a growing problem in most developed countries and is responsible for a significant degree of morbidity and mortality in the Western world. There are several facets to the problem of obesity:

• The prevention of obesity
• The correction of obesity
• The population-based approach
• The individual approach.

Prevention is better than cure and easier. The population-based approach is very important but the doctor in his surgery will have to cope with the individual and so this will be the thrust of this article.

You may wish to read our related record on Obesity in Children for more information about this problem in children and young people.

• According to 2007 figures, about 24% of adults are obese and 61.6% are overweight or obese.⁵ This number rises with age, particularly between 35 and 64.
• Obesity is approaching smoking as the major avoidable cause of premature death but, as deaths from obesity are about 30,000 a year⁶ compared with 110,000 for smoking, it still seems to be some way behind. Obese smokers are at particular risk.
• Obesity is also said to cause 18 million days lost from work due to illness each year.⁷
• Several factors have now been shown to predict the development of obesity in individuals, such as a family history of obesity, lifestyle, diet and socio-economic factors.⁸

Genetic factors

The medical profession is traditionally sceptical about claims that obesity 'runs in the family'. However, the recent mapping of the human genome, combined with evidence from single-gene mutation cases and animal cross-breeding experiments, have identified a significant link between genetic factors and obesity. Over 600 genes, markers and chromosomal regions have now been identified.⁹ It is emerging that obesity is the result of a complex pathophysiological pathway involving many factors that control adipose tissue metabolism. Cytokines, free fatty acids and insulin all play a part and genetic defects are likely to have a significant effect on the fine balance of this process.¹⁰

• A patient may present directly asking for help.
• Confrontation of the problem may arise opportunistically when the patient presents for something else.
• It may be a related problem for the patient with diabetes, coronary heart disease, osteoarthritis or snoring.

The following groups are particularly in need of help and advice:

History

• Physical or psychological problems associated with obesity.
• Ask: "Why do you want to lose weight?" The response may give an indication of motivation.
• Past medical history including history of dieting.
• Social history including diet, exercise, occupation, smoking.
• Family history including history of obesity, diabetes, heart disease.

• Oral hypoglycaemic agents, especially sulphonylureas and thiazolidinediones ('glitazones') - so use metformin first-line.
• Antidepressants including tricyclics, mirtazapine, monoamine oxidase inhibitors.
• Anticonvulsants, particularly sodium valproate, gabapentin, vigabatrin.
• Antipsychotics, especially the atypical antipsychotics amisulpride, aripiprazole, clozapine, olanzapine, quetiapine, risperidone, and zotepine.
• Corticosteroids
• Oral contraceptives, hormone replacement therapy.
• Beta-blockers.
• Pizotifen.

• Hypothyroidism.
• Cushing's syndrome.
• Growth hormone deficiency.
• Polycystic ovary syndrome.
• Hypothalamic damage.
• Genetic syndromes associated with hypogonadism.

Examination

• Weight, height and BMI.
• Blood pressure measurement - using appropriately sized cuff.
• Waist circumference should be no more than 88 cm in women and 102 cm in men.
• Bioelectrical impedance analysis gives a more accurate assessment of body fat and lean tissue mass. This is usually unnecessary and the other measures can all be made with simple equipment found in any surgery.

Investigations

Consider:¹¹

• Urinalysis - for glucose and protein.
• Microalbuminuria screen - the value of this test is not limited to diabetics.¹²
• U&E and LFTs.
• Fasting blood glucose unless already known to be diabetic.
• Fasting lipid profile.

In addition, a few other investigations may be required as indicated by history and examination.

• Hormone profile including sex hormones and cortisol. Hormonal causes of obesity are rare and cortisol may be slightly elevated simply by obesity.
• TSH - hypothyroidism is a rare cause of obesity and does not cause gross obesity.
• Other investigations, as suggested by co-morbidities, e.g. ECG, CXR.

Risks of obesity

The National Audit Office (NAO) report included a calculation of relative risks of other diseases resulting from obesity. The risks are just averages and risks increase with increasing obesity.

Obesity is an important risk factor in the development of chronic respiratory disorders such as COPD, asthma, obstructive sleep apnoea and obesity hypoventilation syndrome.¹³

If the person develops a surgical condition, diagnosis is more difficult and almost every post-operative complication is more frequent, including deep vein thrombosis, chest infection and wound dehiscence. Not only is osteoarthritis more common but treatments such as total hip replacement are more likely to be problematical in obesity.

Obesity increases the risk of breast cancer¹⁴ and carcinoma of the endometrium. Polycystic ovary disease is usually a disease of the obese. Obesity impairs fertility, especially in the female. Obesity may account for as much as 65% of type 2 diabetes.¹⁵

Benefits of weight loss

If an obese person loses 10% of body weight, it is said to confer the following benefits:

• In those with hypertension there is a fall of 10 mmHg in both systolic and diastolic pressure.
• In newly-diagnosed diabetics, an abnormal fasting blood glucose falls in 50%.
• In impaired glucose tolerance:
  • there is >30% fall in fasting or 2 hours insulin levels
  • >30% rise in insulin sensitivity
  • 40% to 60% reduction in the rate of progress to overt diabetes
• Lipid profiles improve with:
  • 10% fall in total cholesterol
  • 15% fall in LDC
  • 8% rise in HDC
• Mortality improves with:
  • >20% fall in all cause mortality
  • >30% fall in mortality related to diabetes
  • >40% reduction in mortality related to obesity

There is no quick fix. The World Health Organisation sees obesity as a chronic disease. Management is not simply helping to shed some unwanted weight but a long-term approach to change attitude, habits and values for the rest of that person's life.

General points

• The majority of obese patients can be managed successfully by the Primary Health Care team with only a very few requiring referral for specialist help.¹
• Many practices offer weight management clinics but this is not the only source of help. Some people may prefer to attend WeightWatchers® or similar groups.
• The following should be included in a plan of action:¹¹
  • Identify the causes that have made the person obese. There are probably several contributory factors.
  • Reiterate why the patient wants to lose weight to emphasise potential benefits and incentives and perhaps to ascertain the degree of motivation.
  • Examine what can be done to facilitate weight loss (e.g. exercise programme).
  • Set realistic targets for rate of loss of weight and desired end point. For a person who has a BMI above 35, the aim of a BMI of less than 25 is probably unrealistic.

Overview of management of different categories of obesity¹

• Overweight
  • Low waist circumference (<80 cm in women, <90 cm in men) - general advice on weight and lifestyle.
  • High waist circumference - structured advice regarding diet and exercise.
  • Co-morbidities - structured advice on diet and activity; consider drug treatment after evaluating effect of lifestyle changes.
• Obese (I)
  • No co-morbidities - structured advice regarding diet and exercise.
  • Co-morbidities - structured advice on diet and activity; consider drug treatment after evaluating effect of lifestyle changes.
• Obese (II)
  • No co-morbidities - structured advice on diet and activity; consider drug treatment after evaluating effect of lifestyle changes.
  • Co-morbidities - structured advice on diet and activity; consider drug treatment after evaluating effect of lifestyle changes. Consider referring for surgery (follow local protocol).
• Obese (III)
  • Structured advice on diet and activity. If available, may need to be via a specialised weight management programme.
  • Consider starting drug treatment after evaluation of lifestyle changes.
  • Consider referring for surgery (follow local protocol).

Diet and exercise

Aim for both dietary modification and the initiation of exercise. Losing weight without exercise is very difficult. This is one reason for early intervention, before exercise is severely limited by morbid obesity, coronary heart disease, severe COPD, severe osteoarthritis or other such diseases that prevent physical exertion. The initial aim should be towards a daily 500 Kcal deficit of energy requirements through change in dietary habits and exercise.⁸

Diet

Diet and cognition - the first problem may be to convince the patient that he is eating too much. It is important to explain to the patient that the equation about calories in and calories out has no exception. It may be helpful to ask the patient to keep a food diary, including all snacks and drinks taken.

Dietary advice - there are many different approaches to dieting; be flexible to find the one that suits the individual. Useful tips are provided by the Norfolk and Norwich University Hospital.¹⁶There may be occasions where there is benefit in referral to a dietician. However, if more than a tiny fraction of obese people within the catchment area is referred, it would swamp the service. The practice may have diet sheets to hand out.

Exercise

Value of exercise - this is more than just the calories expended in the session. It tends to increase basal metabolic rate and, after vigorous exercise, metabolism is stimulated for the next 36 hours. It also helps people to feel good about themselves.

Realistic expectations - people who are obese may have done no exercise for many years. It is important to discuss the options to find something appropriate and sustainable. It must also be something that the individual will enjoy or he will not persevere. An overambitious programme is doomed to failure. An inadequate programme will confer no benefit. See record on Physical Training.

Expert advice - this is that patients should be encouraged to take 30 to 40 minutes of sustained exercise at least 5 times per week¹⁷ and introduce more exercise into their daily routine.

Drug management

General points

• Drugs have a limited role in the management of obesity. Their use is governed by strict criteria which should be met before medication is prescribed.¹ These criteria are laid down by NICE and the licensing requirements of the drug manufacturers.¹¹
• Anti-obesity drugs should only be considered after diet, behavioural changes and exercise have been tried and evaluated. If the patient's weight has reached a plateau despite these measures, drug treatment may be considered.
• The choice of drug should be made after discussing with the patient the risks and benefits, mode of action, monitoring requirements, and possible impact on the patient's motivation. Information and support on dietary, exercise and behavioural changes should be maintained.
• Drug treatment may be used to maintain weight loss, rather than continue to lose weight.
• Vitamin and mineral supplements should be considered, particularly for vulnerable groups like the elderly and growing adolescents.
• Type 2 diabetics may lose weight at a slower rate and appropriate allowance should be made.
• Regular review of adverse effects and to reinforce lifestyle advice is important.
• People being withdrawn from drugs should be offered support because it is at this time that their self-confidence and belief in their ability to make changes may be low.

Orlistat¹⁸

• Action - orlistat is a lipase inhibitor which acts by reducing the absorption of dietary fat. About 30% of the fat that would otherwise be absorbed passes straight through to the large bowel.¹¹
• Effectiveness^11,19 - this drug has a good pharmaco-economic profile.²⁰ Clinical trials suggest a moderate weight loss compared to placebo - about 2-5 kg over a year. There is also a small but significant reduction in total cholesterol, the ratio of total cholesterol to high-density lipids, and systolic and diastolic blood pressure. Most patients gain weight after stopping treatment but trials suggest it takes three years to gain weight lost in one year on the drug.
• Indications - individuals aged between 18 and 75¹ with a BMI of 28 kg/m² or more in the presence of significant co-morbidities (e.g. type 2 diabetes, high blood pressure, hyperlipidaemia) OR a BMI of 30 kg/m² or more with no associated co-morbidities. These individuals should be on a mildly hypocaloric, low-fat diet.
• Prescription
  • Availability²¹ - this is now available over-the-counter (OTC) to individuals with the above criteria. The recommended OTC dose is 60 mg three times a day and treatment under pharmacist care should not exceed 6 months. Pharmacists should check the patient's BMI on each occasion a request is made. There has been some resistance among medical professionals with regards to the benefits at this lower dose, the potential lack of ongoing professional support and monitoring and the possibility of demotivation in the absence of rapid results. There have also been concerns that this initiative will detract from the message about eating less and exercising more.Time will tell whether these fears are justified.
  • Cautions - absorption of fat-soluble vitamins may be impaired. If on long-term therapy, monitor A, D, E and beta-carotene levels and prescribe supplementation if appropriate. Additional contraception may be needed in women experiencing marked gastrointestinal side-effects (e.g. diarrhoea). Underlying kidney disease may result in hyperoxaluria and oxalate nephropathy.
  • Contra-indications - chronic malabsorption syndrome, cholestasis, pregnancy and breast-feeding.
  • Interactions²² - ciclosporin (reduced bioavailability), acarbose (lack of pharmacokinetic data), amiodarone (reduced plasma concentrations), coumarins (enhanced anticoagulant effect), anti-epileptics (decreased absorption). The lipophilic drugs fluoxetine and simvastatin do not seem to be affected by orlistat.²³
  • Common problems - abdominal discomfort/distension, liquid oily stools, faecal urgency and increased frequency, flatulence. More so if diet contains 2,000 kcal/day and is high in fat. Other common problems include headaches, upper respiratory tract infections and hypoglycaemia. Less frequently: rectal pain, menstrual irregularities, anxiety, fatigue.¹⁹ Hepatitis has been reported.²⁴
• Initiation - prescribe one tablet (120 mg) before, during or after each main meal (dose may be missed if meal contains no fat). No more than three tablets in a day.
• Monitoring¹ - check weight at 3 months and 6 months. If unbalanced diet, also monitor fat-soluble vitamin levels. Specifically enquire about side-effects (especially gastrointestinal) and look for drug interactions.
• Ending treatment - treatment should only be continued beyond three months if a further 5% of body weight has been lost since start of treatment (this target may be made more lenient for type 2 diabetics). The use of drug treatment for longer than 12 months (usually for weight maintenance) should be made after discussing potential benefits and limitations with the patient.

Sibutramine²⁵

• Action - this is a centrally-acting serotonin and noradrenaline reuptake inhibitor which has the effect of promoting satiety and increasing energy expenditure.²⁶
• Effectiveness^26,27 - Clinical trials suggest significant weight loss - 5-10% of initial body weight depending on dose, over a year.
• Indication - individuals aged between 18 and 65¹ with a BMI of 27.0 kg/m² or more and other obesity-related risk factors such as type 2 diabetes or dyslipidaemia OR a BMI of 30.0 kg/m² or more.
• Prescription - Ongoing professional support should be available:
  • Availability - prescription only.
  • Cautions - hypertension, epilepsy, sleep apnoea syndrome, hepatic or renal impairment (increased plasma levels of sibutramine reported), family history of motor or verbal tics and ensure women of child-bearing age are using adequate contraception. Do not prescribe monoamine oxidase inhibitors within 2 weeks of stopping sibutramine.¹
  • Contra-indications²⁷ - psychiatric illness (especially major eating disorders and Tourette's syndrome). History of coronary artery disease, congestive heart failure, tachycardia, peripheral arterial occlusive disease, arrhythmias, cerebrovascular disease, and sympathetic nervous system stimulation. Uncontrolled hypertension (>145/90 mmHg)¹, hyperthyroidism, phaeochromocytoma, prostatic hypertrophy with urinary retention, angle-closure glaucoma, drug abuse and alcoholism, pregnancy and lactation.
  • Interactions - psychoactive drugs (increased risk of CNS toxicity with noradrenaline re-uptake inhibitors, SSRIs, tricyclics, antipsychotics, moclobemide, tryptophan) and anticoagulants, aspirin, NSAIDs (increased risk of bleeding).
  • Common problems - very common: constipation, dry mouth, insomnia; common: tachycardia, palpitations, raised blood pressure, vasodilatation, nausea, haemorrhoid aggravation, light-headedness, paraesthesiae, anxiety, headache, sweating, taste perversion.
• Initiation - start at 10 mg daily in the morning, increased if weight loss less than 2 kg after 4 weeks to 15 mg daily.
• Monitoring - NICE recommends that sibutramine should not be prescribed unless there are adequate arrangements for monitoring both weight loss and adverse effects (specifically pulse, blood pressure and mood). Check BP and pulse every 2 weeks for the first 3 months, every month for the next 3 months, and then 3 monthly thereafter. Discontinue treatment if at 2 consecutive visits:
  • BP rises above 145/90 mmHg
  • BP rises by >10 mmHg from baseline
  • Resting pulse rate rises by >10 bpm¹
  Advise patients to report chest pain, ankle oedema or dyspnoea (all symptoms of primary pulmonary hypertension). Not reported with sibutramine but characteristic of anti-obesity drugs as a class.²⁸
• Ending treatment - discontinue if weight loss stabilises at less than 5% of their initial body weight or if there is less than 2 kg weight loss after 4 weeks at higher dose. Also stop if they fail to lose at least 5% of body weight after 3 months or if they regain ≥3kg after previously achieved weight loss. Continue treatment beyond 3 months only if 5% initial body weight or more lost (less stringent targets for type 2 diabetics). Not licensed for use beyond 12 months.

Rimonabant^29,30,31

Rimonabant was a selective cannabinoid 1 (CB1) receptor antagonist which has now had its marketing suspended. The European Medicines Agency completed a review of rimonabant (Acomplia®, a treatment for obesity) after concerns about its psychiatric safety - the benefits of rimonabant do not outweigh the risks of psychiatric reactions in clinical use.

• Patients who are currently taking rimonabant should consult their doctor or pharmacist at a convenient time to discuss their treatment. If patients wish to stop taking rimonabant, it is safe to do so at any time.
• Prescribers should not issue any prescriptions for rimonabant, and should review the treatment of those who are currently taking this medicine.
• Patients in clinical trials should contact the trial administrators.

Which drug?

A meta-analysis of 7 randomised controlled trials suggested that sibutramine was more effective than orlistat. There are however significantly more adverse effects and contra-indications with sibutramine. Choice should therefore be tailored to the individual patient. There is no current evidence to support the use of orlistat and sibutramine in combination.³² There are still unanswered questions in this field of therapy.

Surgery

See our record on Bariatric Surgery.

Alternative or complementary therapies

A number of such therapies has been put forward as remedies to the problem and may be very attractive to prospective customers. However, the evidence base for these treatments is really not there. The exception has been with acupuncture. A recent study has met NICE's selection criteria but as yet, awaits full appraisal.³³

Psychological aspects

Consider cognitive and behavioural therapy to assist in behaviour modification, i.e. help the patient to identify the wrong attitudes and actions in their lives, understand why they are wrong and need to be rectified, identify correct responses and to implement them. There may be "comfort eating" or even clinical depression that needs treatment.¹

As with any chronic disease, follow-up must be arranged. This implies interest in the patient's progress. A fortnight to a month would be appropriate at first, with intervals getting longer with time but treat it as a chronic disease. The practice may have a nurse-run weight control clinic. The achievement of a target weight is not the end of the process. Obesity is a chronic disease and needs to be managed throughout the person's life as relapse is common. "Yo-yo dieting" with weight going up and down is undesirable and unhealthy.

Consider secondary care referral if:

• There are underlying causes which need investigating
• There are complex co-morbidities
• If conventional treatment has failed in primary care
• If specialist interventions may be needed (e.g. very low calorie diet)

For those who are obese, any loss of weight is beneficial and, within reason, the more the better; most of the complications of obesity can be reduced by weight loss.¹ However, the outlook is generally poor. Many people who have consulted a doctor about weight achieve little in terms of weight loss, or the loss is only temporary. Nevertheless, the stakes are such that every encouragement should be given to those who wish to try.

It is feared that by 2050, up to 90% of adults will be overweight or obese. In the UK, obesity costs the NHS an estimated £4.2 billion but this is set to double by 2050 if current trends continue.

The problem of obesity needs to be addressed through a broad range of measures covering different aspects contributing to it. Thus, public health strategies are linked with town planning, convenience store planning, school food and exercise programmes and good information campaigns for example. The National Obesity Observatory has been set up in an effort to collate the research information and to provide a single point of contact for wide-ranging authoritative information on data and evidence relating to obesity, overweight, underweight and their causes in order to support policy makers. A link to its website is provided in the 'Internet and further reading' section below.

This record has focused on the management of obese individuals but the future lies in the management of an obese society and, more particularly, in curbing and perhaps reversing the growing trend.