The weight-loss industry never seems to slim down. Now it is no longer just liposuction that surgery offers. Bariatic surgery, which deals with the treatment of obesity, is another option, but isn’t a quick fix. Like any operation, it has its risks – and people carrying extra weight often face problems with anaesthesia.

The National Institute for Health and Clinical Excellence (Nice) recommends weight-loss surgery, but only in specific circumstances: it is considered suitable for adults with a body mass index of greater than 40kg/m2, or for those with a BMI above 35kg/m2 who have another condition such as high blood pressure or type 2 diabetes and who have been unable to lose weight through diet, exercise or medication. The patient must receive intensive care via a specialist obesity service, and is encouraged to submit to long-term follow-up. Nice also recommends that surgery is used in the first line where the BMI is above 50kg/m2.

This kind of surgery usually consists of reducing the size of the stomach or bypassing it. It is often successful: one study found that there was a mean reduction in body weight of 23.4 per cent after surgery. However, this study didn’t compare surgery with medication used for weight loss – and indeed a lack of comparative evidence is one criticism levelled at the surgery.

So is the risk worth it? Some studies put the mortality rate for surgery at 0.02 to 1 per cent, but one widely quoted study suggests a rate of 1.9 per cent within 30 days. Other studies suggest that around 13 per cent of people have complications, including bleeding, blood clots, infection or even heart attacks. But people with this degree of obesity have a high risk of health problems even without surgery, so the real question is whether the risks of surgery outweigh the risks of not having it.

Other reviewers have pointed out that most of the studies so far have been done on younger white women, and that the results might not be applicable to older people, men, or those from other ethnic groups. The other issue is that of longer-term problems resulting from the surgery. Some patients report indigestion; others become deficient in vitamins normally absorbed from the (now deliberately) non-absorbing bowel. Because of this, vitamin tablets don’t work, as these aren’t absorbed either, resulting in what have been memorably described as “very nutritious stools”. More research is needed, and if you are considering this type of operation, my only real suggestion is to make sure your team intends to include you in researching the outcomes of the procedure.

http://www.bmj.com/cgi/content/full/330/7497/921-a

Margaret McCartney is a GP in Glasgow
margaret.mccartney@ft.com

For lively discussion of the latest medical issues go to Margaret McCartney’s blog