Obesity

Pre-referral guidelines for primary care providers

Obesity is classified as a BMI >95th percentile for age- and sex-matched BMI.

Overweight is classified as a BMI >85th percentile for age- and sex-matched BMI.

Obesity and overweight are very common problems in Australia, with rates increasing rapidly. Increasing data suggests that overweight infants and toddlers are more commonly overweight adults.

Diagnosis

Overweight and obesity is determined by calculating and plotting body mass index (BMI). Abdominal (waist) circumference is also used. Once diagnosed, monitoring for complications remains very important (see management below).

Note that it is uncommon for a medical diagnosis or syndrome to be the cause of overweight or obesity, however it must be considered in any workup (particularly in those with short stature, developmental delay or dysmorphism).

The diagnosis of metabolic syndrome (in adults) requires at least three of:

  • waist circumference > 102 cm (male) or > 88 cm (female)
  • triglycerides > 150 mg/dL
  • HDL < 40 mg/dL (male) or < 50 mg/dL (female)
  • BP > 130/85 mmHg
  • fasting BSL > 5.5mmol/L

Practice points

  • Obesity is classified as a BMI >95th percentile for BMI. Overweight is classified as a BMI >85th percentile for BMI.
  • Note that it is uncommon for a medical diagnosis or syndrome to be the cause of overweight or obesity, however it must be considered in any workup, particularly in those with short stature, developmental delay or dysmorphism.
  • management of obesity requires exclusion of medical causes, monitoring for complications and management strategies.

Management

Management of obesity requires three main steps:

  • exclusion of medical causes
    • it is uncommon for children to have an underlying medical cause for weight problems, although does become more likely in those with short stature, developmental delay or dysmorphism.
    • hypothyroidism
  • monitoring for complications
    • examination: weight & height, BMI, waist circumference, BP and pulse, acanthosis nigricans, hepatomegaly, striae
    • investigations: LFT, fasting lipids (incl LDL/HDL) & cholesterol, fasting glucose, fasting insulin (debatable use), PCOS screen (if clinically indicated), liver ultrasound.
  • management strategies
    • lifestyle modification - diet and exercise form the key components to the management of overweight & obesity
    • medication - consider in certain circumstances
      • antihypertensives
      • metformin (insulin resistance, weight)
      • statins, bile-acid binding resins & cholesterol-absorption inhibitors

Referral pathways