Effectiveness of Bariatric Surgery

The NHMRC guidelines advise that patients receiving bariatric surgery need to be appropriately selected and prioritised according to clinical need and capacity to benefit from the surgery (Table 6).

Table 6. Selection criteria for bariatric surgery

Health benefits

The association between bariatric surgery and improvement in obesity-related comorbidities has been well documented.

Bariatric surgery provides a dramatic reduction or resolvement of many serious comorbiditities such as:

  • Type 2 diabetes
  • Metabolic syndrome
  • Hypertension
  • Dyslipidemia
  • Gastroesophageal reflux
  • Asthma
  • Arthritis/joint pain
  • Polycystic ovarian syndrome
  • Depression
  • Sleep apnoea.


Bariatric surgery has been shown to be cost-effective when compared to conventional and non-surgical treatments (see Appendices 1 and 2).

A recent Australian study, a 2-year randomised controlled trial involving 60 obese participants (BMI>30 and <40 kg/m2), showed that surgically induced weight loss appears to be a cost-effective intervention for managing recently diagnosed type 2 diabetes in obese patients (Figure 5). Their results showed that the mean medication costs were 1.5 times higher for conventional patients, primarily due to greater use of diabetes medication (mean medication cost: $900 AUD (2006) per surgical patient and $1,400 AUD (2006) per conventional therapy patient). The authors concluded that the cost of undergoing surgery will be offset by avoidance of ongoing costs of managing obesity (e.g. cost of medication).

Figure 5. Mean medication cost per patient over time

Source: Keating et al., 2009.