Growing epidemics

August 2013

FocusGrowing epidemics

Obesity

Recommendations for management in general practice and beyond

Volume 42, No.8, August 2013 Pages 532-541

Mariee Grima

John B Dixon

Background

It is well recognised that Australia has one of the highest prevalences of overweight and obesity in the developed world, and that this is the greatest contributing factor, along with ageing, to the chronic disease burden in our society. Predictions are confronting; close to 80% of Australian adults are predicted by be obese by the year 2025. The determinants of obesity are multifactorial and are influenced by early life environments as well as genetics. Prevention is failing due to many factors including a poor understanding of these determinants as well as reluctance to act at a government/community level.

Objective/s

This article aims to provide a practical approach to weight management in general practice with a focus on some of the more intensive interventions beyond the first line lifestyle modification advice.

Discussion

General practitioners are often well placed to identify overweight and obesity. Patient engagement in management is critical, as for any chronic disease. Treatment needs to be evidence based and focused on a broad range of health outcomes, not simply on weight. Intensive interventions to potentiate weight loss may involve use of very low energy diets, pharmacotherapy and bariatric surgery. Referral to specialist weight assessment and management clinics, where available may be appropriate, particularly for complex cases with more severe comorbidity.

Obesity is a complex, chronic, relapsing condition and, along with ageing, is the greatest contributing factor to chronic disease burden in our society. It is well recognised that Australia has one of the highest prevalences of overweight and obesity in the developed world, affecting over 60% of adults and 25% of children and adolescents; this figure is predicted to increase to close to 80% of adults by the year 2025.1,2 One-quarter of Australian adults are considered to be obese (body mass index [BMI] >30 kg/m2), and numbers affected by this more severe form of overweight are rising exponentially.2,3 The economic burden associated with the epidemic proportions of obesity in Australia has been attributed to the overall healthcare cost of $58.2 billion in 2008, with direct healthcare costs in excess of $8 billion per year.4 These figures are only likely to increase, further straining health services.

The major determinants of obesity are multifaceted, surprisingly poorly understood and extend well beyond simplistic explanations about high energy Western diets and obligatory reductions in human movement.5 The interplay between humans and the environment, influenced by genes, epigenetic default metabolic programming, the intrauterine environment and early infant feeding practices set the scene in the early years for weight trajectory throughout life.6 The list of comorbidities associated with both excess weight and the metabolic consequences of obesity is extensive and encompasses chronic disease, as well as functional and psychosocial disability (Table 1).7 Furthermore, it is well established that increasing levels of obesity are associated with poor overall quality of life and increased morbidity and mortality.8

Table 1. Health risks associated with overweight and obesity in adults
Body systemHealth risk
Cardiovascular Stroke
Coronary heart disease
Cardiac failure
Hypertension
Endocrine Type 2 diabetes
Polycystic ovary syndrome
Gastrointestinal Non-alcoholic fatty liver disease
Gallbladder disease
Pancreatic disease
Gastro-oesophageal reflux disease
Cancers of the bowel, oesophagus, gall bladder and pancreas
Genitourinary Chronic kidney disease – glomerulopathy End-stage renal disease
Kidney cancer
Kidney stones
Prostate cancer
Stress urinary incontinence (women)
Sexual dysfunction (men)
Pulmonary Obstructive sleep apnoea
Obesity hypoventilation syndrome
Asthma
Musculoskeletal Osteoarthritis – especially the knees
Spinal disc disorders
Lower back pain
Disorders of soft tissue structures such as tendons, fascia and cartilage
Foot pain
Mobility disability (particularly in older adults)
Reproductive health Menstrual disorders
Miscarriage and poor pregnancy outcome
Infertility/sub-fertility
Breast cancer (postmenopausal women)
Endometrial cancer
Ovarian cancer
Mental health Depression
Eating disorders – binge eating disorder
Reduced health – related quality of life
Adapted with permission from National Health and Medical Research Council. Clinical practice guidelines for the management of overweight and obesity in adults, adolescents and children in Australia. Canberra: NHMRC, 2013

Prevention of obesity is failing for many reasons including: a poor understanding of the obesity determinants and evidence regarding what influences them, political inertia associated with a modern market economy, and philosophical views of personal responsibility versus regulation and whole of community involvement. Treatment strategies for obesity should ideally follow a chronic disease model of care with a patient centred focus and initial use of lifestyle and micro-environmental interventions, with escalation to more intensive interventions as dictated by the severity of disease and response to therapy.9,10 Treatment needs to be evidence based and focused on a broad range of health outcomes, not simply on weight. Excellent management of medical, psychological and physical co-morbidity are critical to engaging patients in weight loss interventions, improving function and quality-of-life, and reducing morbidity and mortality. It is also important to note that not all methods to treat obesity are equally effective. This article addresses first-line treatment with lifestyle modification in general practice and then focusses on appropriate use of more intensive treatments to support weight loss as well as identifying indications for referral to specialist weight management clinics.

Weight management in general practice

General practitioners are often the first healthcare providers to identify overweight or obesity. Treatment should be individualised with careful consideration given to the severity of the problem and associated complications using the 5As approach for weight management: Ask and Assess, Advise, Assist and Arrange (Table 2).7

Table 2. The 5 As overweight and obesity management model for adults and post-pubertal adolescents7

Establish a therapeutic relationship, communicate and provide care in a way that is person centred, culturally sensitive, non-directive and non-judgemental

Ask and Assess Standard careActive management
BMI <25BMI 25–29.9BMI 30–34.9BMI 35–39.9BMI >40
Routinely assess and monitor BMI and waist circumference (WC) Routinely assess and monitor BMI and WC
Discuss if BMI and/or WC increasing
Screen for and manage comorbidities
Routinely assess and monitor BMI and WC
Discuss health issues
Screen for and manage comorbidities
Assess other factors related to health risk
Blood pressure, lipid profile, fasting glucose, liver function tests, and ask about symptoms of sleep apnoea and depression
Advise Promote benefits of healthy lifestyle
Explain benefits of prevention of weight gain and maintenance of healthy weight
Promote benefits of healthy lifestyle
Explain benefits of weight management
Assist   Assist in setting up weight loss program:
  • Advise lifestyle interventions
  • Based on comorbidities, risk factors and weight history, consider adding intensive weight loss interventions (eg. VLEDs, pharmacotherapy, bariatric surgery)
  • Tailor the approach to the individual
  • Refer to multidisciplinary team for specialist treatment recommendations. Suitable patients include those with severe complex obesity for example those with a BMI >40, BMI >35 with any serious comorbidity, and those BMI 3035 with serious comorbidity and a positive weight trajectory.
Arrange   Review and monitoring
Long term weight management
Referral to specialist weight management clinic if indicated

It is important to assess the level of obesity by BMI, distribution of weight (waist circumference), and the extent of co-morbidity, in order to provide effective treatment and assess level of disease risk (Table 3).7,11,12 Patient engagement as a central agent in management is fundamental. The therapeutic partnership is critical in delivering long term health outcomes as for any other chronic disease.9

Table 3. Classification of disease risks* by WHO BMI classification and WC thresholds
BMI (kg/m2)ClassificationMen WC 94–102 cm
Women WC 80–88 cm
Men WC >102 cm
Women WC >88 cm

18.5–24.9

Normal weight†

25–29.9

Overweight

Increased

High

30–34.9

Obese class I

High

Very high

35–39.9

Obese class II

Very high

Very high

≥40.0

Obese class III

Extremely high

Extremely high

* Disease risk for type 2 diabetes, hypertension and cardiovascular disease
† Increased WC can also be a marker for increased risk even in persons of normal weight
Reproduced from the Scottish Intercollegiate Guidelines Network (SIGN). Management of obesity. A national clinical guideline. Edinburgh: SIGN; Year. (SIGN publication no. 115). [cited 10 July 2013]. Available from URL: www.sign.ac.uk

Optimal management of obesity in time poor general practice requires a team care approach involving those specifically trained and experienced in obesity management. These may include dieticians, practice nurses, commercial weight management programs, exercise physiologists and psychologists.7 General practitioners are encouraged to identify, engage and regularly communicate with local weight management providers and to refer those with resistant severe complex obesity for specialised assessment and management recommendations.7 The evidence demonstrating the benefits of weight loss is well documented. Modest weight loss of 5–10% of starting weight can result in significant health benefits, with substantial weight loss offering even greater improvements in obesity related comorbidities. Weight loss for most isn’t easy. Regulation of body weight is carefully controlled by a range of highly efficient homeostatic mechanisms that work to prevent weight loss rather than to protect against weight gain.13–15 In addition, factors predisposing an obese patient to weight gain – such as certain medications, smoking status, a patient’s weight history and readiness to change – can significantly impact on weight loss success.7 These factors and mechanisms challenge successful weight loss and long term weight maintenance for the obese patient and should be taken into careful consideration, especially when planning interventions.

Despite these difficulties, lifestyle interventions remain the first line treatment for overweight and obesity. General practitioners should make patients aware of the health risks associated with increases in BMI and the benefits that can be derived from lifestyle change, even when independent of weight loss.7 The initial approach to weight loss and lifestyle change should include an emphasis on healthy eating with a subsequent reduction in energy intake, in line with the Australian Dietary Guidelines 2013.16  Increasing levels of physical activity and reductions in sedentary behaviour should also be encouraged.7,12,16,17 Psychological therapies to support behaviour change may also be of assistance.

Intensive interventions

Intensive interventions to potentiate weight loss may involve use of very low energy diets (VLEDs), pharmacotherapy and bariatric surgery. A summary of the weight loss effects of each weight management intervention is shown in Figure 1.

Figure 1. Average weight loss of subjects completing a minimum 1 year weight management intervention

Figure 1. Average weight loss of subjects completing a minimum 1 year weight management intervention; based on review of 80 studies (N=26 455; 18 199 completers [69%])26

Very low energy diets

VLEDs (<800 kcal/day or <3350 kJ/day] are indicated for use in patients with a BMI >30 or BMI >27 with obesity related comorbidities. When used under the medical supervision of a GP and dietician, VLEDs are able to induce rapid weight loss and have been shown to achieve an average weight loss of 18–20% with better sustained weight reduction.18 In addition to weight loss effects, the rapid weight loss offered by VLEDs has been shown to improve glycaemic control in patients with type 2 diabetes, improve blood pressure and reduce total cholesterol. VLEDs involve replacing all meals with a specific meal replacement formula (additional food can be carefully added) during the intensive early phase. These high protein-low carbohydrate diets induce fat burning and mild ketosis, which results in suppression of hunger and promotion of satiety. Treatment duration with a VLED is generally 8–12 weeks, however, safe year-long use under strict medical supervision has been reported.19 In addition, VLEDs are safe and effective when used to assist with long term weight maintenance in either an intermittent or on-demand fashion.20

VLEDs may not be suitable for use for all obese patients and it is important to consider the costs associated with purchasing suitable nutritionally complete meal replacements. VLEDs are contraindicated for use in pregnant or lactating women, infants, children, adolescents (under 18 years), elderly (over 65 years), patients with a history of psychological disturbances, alcohol misuse or drug abuse, in the presence of porphyria, recent myocardial infarction or unstable angina.7 Monitoring and support of patients on VLEDs is required for success (Table 4). Training on the use of VLEDs is available and should be sought by practices wanting to effectively utilise this intensive intervention with suitable overweight or obese patients.

Table 4. VLEDs: Adverse effects, monitoring and review in general practice7,19
Adverse effects Common Sensitivity to cold, dry skin, temporary rash, temporary hair loss, postural hypotension, dizziness, fatigue, diarrhoea, constipation, muscle cramps, bad breath, irritability, menstrual disturbances
Rare and serious Gallstones, gout, sodium or potassium imbalance, temporary changes in liver enzyme levels, reduced bone mineral density
Monitoring Medical Medical history, physical examination, height, weight, waist and hip circumference, BMI, blood pressure, pulse, electrocardiogram
Blood biochemistry* Full blood count, iron studies, electrolytes, creatinine, uric acid, liver function tests, lipid profile and urinalysis including ketones, pH and microalbuminuria
Medications Anti-diabetic agents (sulphonylureas, thiazolidinediones, insulin), warfarin, lithium, diuretics, anti-psychotics, anti-convulsants (valproate, gabapentin, carbamazepine)
Review frequency GP Each week for 4 weeks, then fortnightly for remainder of intensive phase
Dietician
* Tests carried out on patients should be completed at the beginning of a VLED. An ECG is only needed if there is another indication. Blood biochemistry may be repeated at 6 weeks if indicated by the patients accompanying medical condition and for all after 3 months if they they intend to continue with the intense VLED program.

Pharmacotherapy

Pharmacotherapy for the treatment of obesity should be considered for use as an adjunct to lifestyle intervention in patients with a BMI >30 or BMI >27 with obesity related comorbidities.21 Weight loss medications used in the treatment of obesity can act centrally to increase levels of satiety or act on the gastrointestinal tract to restrict nutrient absorption. Table 5 describes the pharmacological agents that may be used to treat obesity.7,17 Care, consideration and close monitoring is essential when prescribing these medications. The United States Food and Drug Administration (FDA) has recently approved two new medications: lorcaserin and phentermine-topiramate.

Table 5. Weight loss and other medications for treatment of obesity
ActionMedicationIndicationsCommon adverse effectsMean weight loss (compared with placebo)Notes
Dopaminergic agonist Phentermine Management of obesity as a short term adjunct to medically managed comprehensive weight reduction regimen in obesity of BMI >30 or BMI 25–29.9 if associated with comorbidities Palpitations, tachycardia, hypertension, precordial pain, central nervous system stimulation, headache, gastrointestinal upset including constipation, dry mouth, altered taste, micturition disturbance, rash, impotence, libido change, facial oedema 3.6 kg (CI: 6.0–0.6) following 2–24 weeks treatment26 Approved only for short term use – up to 3 months
Pancreatic and gastric lipase inhibitor Orlistat Treatment of obese patients with a BMI >30 and overweight patients with a BMI >27 with associated comorbidities Gastrointestinal upset including oily spotting, flatulence, faecal urgency, loose stools, nausea, dyspepsia, reduced vitamin absorption, headache, kidney stones 2.9 kg (CI: 3.5–2.3) at
1 year27
Low fat diet should be followed
Biguanide Metformin Treatment of type 2 diabetes Gastrointestinal upset, taste disturbance, vitamin B12 depletion, liver function test abnormality, hepatitis, skin reaction Women of reproductive age prone to infertility:
0.68 BMI (CI: 1.13–0.24) following 35 days to 6 months treatment28

Without diabetes treated with atypical anti-psychotics:
4.8% body weight
(CI: 8.0–1.6) following 12–14 weeks treatment29
Not approved for the treatment of obesity
Glucagon-like peptide agonists Exenatide (Byetta) Treatment of type 2 diabetes Gastrointestinal upset, hypoglycaemia, exenatide antibody formation, decreased appetite, headache, hyperhidrosis, jitteriness, asthenia, injection site reaction, nasopharyngitis, upper respiratory tract infection, back pain, cough Without diabetes:
3.2 kg (CI: 4.3–2.1) following minimum 20 weeks treatment30

With diabetes:
2.8 kg (CI: 3.4–2.3) following minimum 20 weeks treatment31
Byetta and Victoza are not yet approved for the treatment of obesity
Liraglutide Treatment of type 2 diabetes Gastrointestinal upset, anorexia, dyspepsia, eructation, gastroesophageal reflux disease, hypoglycaemia, decreased appetite, headache, injection site reaction, upper respiratory tract infection, antibody formation, urticaria, oedema, pancreatitis, thyroid neoplasm, goitre, increased blood calcitonin, renal failure
Serotonin 2C receptor agonist Lorcaserin Management of obesity as an adjunct to medically managed comprehensive weight reduction regimen in obesity of BMI >30 or in overweight of BMI >27 if associated with comorbidities In non-diabetic patient: headaches, dizziness, fatigue, nausea, dry mouth, constipation
In diabetic patient: hypoglycaemia, headache, back pain, cough, fatigue
3.23 kg (CI: 3.75–2.70) at
1 year32
Lorcaserin and Qsymia are both FDA approved, but not yet approved by the TGA for use in Australia
Combined dopaminergic agonist and antiepileptic Phentermine and topiramate Management of obesity as an adjunct to medically managed comprehensive weight reduction regimen in obesity of BMI >30 or in overweight of BMI >27 if associated with comorbidities Paresthesia in the hands, arms, feet, or face, dizziness, dysgeusia, insomnia, constipation, dry mouth, tachycardia, suicidal thoughts 7.5 mg phentermine plus 46.0 mg topiramate:
8.1 kg (CI: 8.5–7.1) following 56 weeks treatment33

15 mg phentermine plus 92 mg topiramate:
10.2 kg (CI: 10.4–9.3) following 56 weeks treatment33

These medicines are not yet approved for use by the Therapeutic Goods Administration (TGA) in Australia.21 It is important to note that the safety and efficacy of co-administration of lorcaserin or phentermine-topiramate with other products for weight loss, and the effects of these medications on cardiovascular morbidity and mortality, have not yet been established.

Surgery

Bariatric surgery should be considered for patients with a BMI >40 or with a BMI >35 with obesity related comorbidities.22 Bariatric surgery is the most effective available treatment for obesity in terms of achieving and maintaining substantial weight loss long term.23 The three most commonly performed procedures in Australia include laparoscopic adjustable gastric banding (LAGB), Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG). We are now starting to learn about how alterations to the gastrointestinal tract, induced by bariatric surgery, reduce hunger, increase satiety and confer other metabolic benefits as well as sustained weight loss.24,25

To date, the long term safety of LAGB and RYGB has been documented, however evidence on long term safety is lacking for the SG. Each procedure is accompanied by its own advantages and disadvantages, and these need to be taken into consideration when assessing a patient’s suitability for surgery (Table 6). Current medical and psychological comorbidities, as well as ability to provide informed consent, will all influence a patient’s suitability for undergoing a particular procedure.7 Patients considering bariatric surgery should be made aware of the commitment to indefinite post-surgical care and long term monitoring from an experienced team.

Table 6. Bariatric surgery: A summary of the characteristics of current conventional procedures24
Surgical procedureDescriptionExcess weight loss at 3–5 years*Percentage mean weight lossPattern of weight lossMorbidity at 1 yearNutritional concernsFollow up requirementsAdvantagesDisadvantages
Laparoscopic adjustable gastric banding (LAGB) Involves placing an adjustable band around the gastroesophageal junction, thereby restricting food intake. The band can be tightened and loosened over time to alter the extent of restriction 54% 20–30% Gradual; usually maximal at 2–3 years 4.6% Low (deficiencies in iron, vitamin B12, folate) Lifelong (assessment and nutritional support), frequent in the first 12 months Effective, with good long term weight maintenance
Ability to adjust the degree of restriction
Reversible
Maintains gastric integrity
Gastric pouch dilatation, erosion of band into the stomach, leaks to the LAGB system, weight regain
Roux-en-Y gastric bypass Is a combination procedure in which a small stomach pouch is created to restrict food intake and the lower stomach, duodenum and first portion of the jejunum are bypassed to produce modest malabsorption of nutrients and energy intake 60%
(75% with banded RYGB)
25–35% Rapid; maximal at 1–2 years 14.9% Moderate (deficiencies in iron, vitamin B12, folate, calcium, vitamin D, copper, zinc) Lifelong (assessment and nutritional support) Very effective with good long term weight maintenance
Few failures
Abdominal pain, staple line leak, stomach ulcer, intestinal obstruction, gallstones, nutritional deficiency, weight regain
Sleeve gastrectomy Involves removing the greater portion of the fundus and body of the stomach, reducing its volume from about 2.5 L to about 250 mL 50–60%
(limited reports at ≥3 years)
20–30% Rapid; maximal at 1–2 years 10.8% Moderate (deficiencies in iron, vitamin B12, folate, calcium, vitamin D, copper, zinc, thiamine) Lifelong (assessment and nutritional support) Allows for rapid weight loss
No dumping syndrome as pyloric portion of the stomach is in tact
Provides fixed restriction and does not require adjustment
Staple line leak, gastroesophageal reflux disease, dilatation of the gastric remnant, weight regain
Contraindications for bariatric surgery: current drug or alcohol abuse; uncontrolled psychiatric illness and lack of comprehension of the risks and benefits, expected outcomes, alternatives and lifestyle changes required with bariatric surgery; the presence or suspicion of esophageal or gastric malignancy; portal hypertension with varices; liver failure; Crohn disease; recently diagnosed malignancy; multiple organ failure; previous gastric or gastrointestinal surgery; recent myocardial infarction (may substantially increase the risk of surgery, later complications or poor outcomes)
* Excess weight defined as the weight of an individual in excess of their weight at BMI 25 kg/m2

Specialist weight management clinics

Unfortunately, specialist weight assessment and management clinics for complex severe obesity are not broadly available, but with the emergence of new drugs, devices and surgical procedures, as well as ever increasing patient numbers; assessment by teams skilled in this area is becoming more necessary. Some major hospitals offer outpatient ‘specialist weight management’ or ‘metabolic’ clinics; however, access is often impeded by very long waiting lists. Medicare Locals may provide a forum for exploring delivery gaps in regional areas particularly. Specialised weight management services would provide advice to the GP similar to that expected from cardiac or diabetes referrals such as an evaluation of the patients, advice regarding the treatment options and a proposal for ongoing shared care. Severe obesity is a serious complex chronic disease and requires this level of expertise and support to optimise health outcomes. 

Conclusion

General practitioners are in a key position to provide support, advocacy and coordinate management for obese patients. The use of intensive interventions should be considered and utilised within the general practice setting and, where indicated, complex obese patients should be referred to specialist weight assessment and management clinics.

Key points

  • Obesity is a complex chronic relapsing condition requiring ongoing management and monitoring from medical and other allied health professionals.
  • Maintained weight loss is a primary, but not the sole, consideration when treating obesity.
  • General practitioners are encouraged to consider the timely use of more intensive treatments to support weight loss beyond that of first line treatment with lifestyle modification.
  • Referral and liaising with specialist weight assessment and management clinics for complex cases can enhance outcomes.

Competing interests: John B Dixon is a board member of Nestle Australia and has received payment for consultancy from Allergan Inc and Bariatric Advantage. John B Dixon has received payments for lectures from iNova Pharmaceuticals and Merck Sharp & Dohme and for development of educational presentations from iNova Pharmaceuticals, and travel expenses from GI Dynamics.
Provenance and peer review: Commissioned; externally peer reviewed.

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Correspondence afp@racgp.org.au

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