When to offer surgery

Bariatric surgery is a treatment option for people with obesity if all of the following criteria are fulfilled:

• They have a BMI of 40 kg/m2 or more, or between 35 kg/m2 and 40 kg/m2and other significant disease (for example, type 2 diabetes or high blood pressure) that could be improved if they lost weight.​

• All appropriate non-surgical measures have been tried but the person has not achieved or maintained adequate, clinically beneficial weight loss.​

• The person has been receiving or will receive intensive management in atier 3 service. (For more information on tier 3 services, see NHS England's report on joined up clinical pathways for obesity.)​

• The person is generally fit for anaesthesia and surgery.​

• The person commits to the need for long-term follow-up.

In addition to the criteria listed above, bariatric surgery is the option of choice (instead of lifestyle interventions or drug treatment) for adults with a BMI of more than 50 kg/m2 when other interventions have not been effective.

The hospital specialist and/or bariatric surgeon should discuss the following with people who are severely obese if they are considering surgery to aid weight reduction:

• the potential benefits
• the longer-term implications of surgery
• associated risks
• complications
• perioperative mortality.

The discussion should also include the person's family, as appropriate.

Choose the surgical intervention jointly with the person, taking into account:

• the degree of obesity
• comorbidities
• the best available evidence on effectiveness and long-term effects
• the facilities and equipment available
• the experience of the surgeon who would perform the operation.

Carry out a comprehensive preoperative assessment of any psychological or clinical factors that may affect adherence to postoperative care requirements (such as changes to diet) before performing surgery.

Orlistat

• Orlistat may be used to maintain or reduce weight before surgery for people who have been recommended surgery as a first-line option, if it is considered that the waiting time for surgery is excessive.

Interventional procedures

NICE has published guidance on the following procedures:

• implantation of a duodenal–jejunal bypass sleeve for managing obesity, which should only be used in the context of research​

• laparoscopic gastric plication for the treatment of severe obesity with special arrangements for clinical governance, consent and audit or research.

Resources and equipment

Surgery for obesity should be undertaken only by a multidisciplinary team that can provide:

• preoperative assessment, including a risk–benefit analysis that includes preventing complications of obesity, and specialist assessment for eating disorder(s)
• information on the different procedures, including potential weight loss and associated risks
• regular postoperative assessment, including specialist dietetic and surgical follow-up
• management of comorbidities
• psychological support before and after surgery
• information on, or access to, plastic surgery (such as apronectomy) where appropriate
• access to suitable equipment, including scales, theatre tables, Zimmer frames, commodes, hoists, bed frames, pressure-relieving mattresses and seating suitable for patients
• undergoing bariatric surgery, and staff trained to use them.

The surgeon in the multidisciplinary team should:

have had a relevant supervised training programme
have specialist experience in bariatric surgery
submit data for a national clinical audit scheme. (The National Bariatric Surgery Registry is now available to conduct national audit for a number of agreed outcomes.)

Revisional surgery

• Revisional surgery (if the original operation has failed) should be undertaken only in specialist centres by surgeons with extensive experience because of the high rate of complications and increased mortality.

Audit, dietetic monitoring and follow-up care

Audit and dietetic monitoring

Provide regular, specialist postoperative dietetic monitoring, including:

• information on the appropriate diet for the bariatric procedure
• monitoring of the person's micronutrient status
• information on patient support groups
• individualised nutritional supplementation, support and guidance to achieve long-term
• weight loss and weight maintenance.

Arrange prospective audit so that the outcomes and complications of different procedures, the impact on quality of life and nutritional status, and the effect on comorbidities can be monitored in both the short and the long term. (The National Bariatric Surgery Registry is now available to conduct national audit for a number of agreed outcomes.

Follow-up care

Offer people who have had bariatric surgery a follow-up care package for a minimum of 2 years within the bariatric service. This should include:

• nutritional monitoring, including screening for protein, vitamin and mineral deficiencies
• monitoring for comorbidities
• medication review
• dietary and nutritional assessment, advice and support
• physical activity advice and support
• psychological support tailored to the individual
• information about professionally led or peer-support groups.

After discharge from bariatric surgery service follow-up, ensure that all people are offered at least annual monitoring of nutritional status and appropriate supplementation according to need following bariatric surgery, as part of a shared care model of chronic disease management.