Should weight-loss surgery be rolled out widely on the NHS, when effectiveness has been shown for less than 1 in 50?
So many adults become chronically obese, and we are now so aware of childhood obesity, that an overweight person’s history of normal weight and eating, or bulimia, or even anorexia nervosa, can be overlooked. The low cost of calories, and other “obesogenic” factors such as increased screen time and reduced exercise can also lead to therapeutic pessimism, despite nearly one-third of adults having normal weight (1).
Given the apparent failure of appetite suppressants and psychotherapy to treat obesity, a more hands-on surgical approach has gained a lot of ground (2). Reviews of bariatric surgery seem to make a well-founded case for wider use of this treatment: randomised controlled trials (RCT’s), the hallmark of proper testing, have been abundant.
But, despite well-documented cases of obesity remitting and relapsing in response to a range of interventions, sometimes with long intervals (Oprah Winfey, perhaps most famously), there has never been a single- or double-blind trial of bariatric surgery, compared with a true “placebo” which would be “sham” surgery: entering the abdomen under anaesthetic but making no further intervention.
Such genuine placebo-controlled surgical trials have been performed in many disorders where psychological factors have been felt to be significant (3). The RCT’s which give an impression of “a good evidence base” for bariatric surgery are mostly of one form of surgery compared with another, or surgery compared with a perhaps dubious non-medication-based intervention.
And anyway, according to a 2009 UK government-funded and -published meta-analysis, research into bariatric surgery has established its effectiveness for only 1 in 50 people who are at risk of health problems from being overweight: “The evidence base for the clinical effectiveness of bariatric surgery for adults with Class I [BMI30-35] or class II [BMI35-40] obesity is very limited.” (4).
Although I support bariatric surgery, and tried unsuccessfully to have it considered for one of my very obese learning disabled patients, four years ago, it appears to be at risk of being over-promoted for less severe disorders. Just like many other treatments in the history of medicine.
It is possible, in my view, that psychotherapists of all kinds (CBT, psychodynamic, 12-step-orientated) have simply not tried hard enough for a group of patients that attracts negative and even punitive public attention (5). Before proper randomised controlled trials of bariatric surgery, it must make sense to keep looking for non-surgical treatments.
(1) 31.7% of English adults were “normal weight” in 2006. The clinical effectiveness and cost-effectiveness of bariatric (weight loss) surgry for obesity: a systematic review and economic evaluation. Picot et al. Health Technol Assess 2009: 1-190, 215-357. [p3]. Available at http://www.hta.ac.uk/execsumm/summ1341.htm
(2) See my Blog piece “No” to the knife, “Yes” to Ritalin? 6th August 2010: https://drnmblog.wordpress.com/2010/08/06/%e2%80%9cno%e2%80%9d-to-the-knife-%e2%80%9cyes%e2%80%9d-to-ritalin/
(3) Laparoscopic excision of endometriosis: a randomized, placebo-controlled trial. Abbott et al. Fertil Steril 2004: p878. http://www.ncbi.nlm.nih.gov/pubmed/15482763
(4) See (1): p157. 67.1% of English adults were either “overweight” or “obese” in 2006, of which 2.2% (1.5% of the whole population) had aBMIabove 40. See (1) p3
[includes comments from the then Royal College of General Practitioners chairman, Professor Steve Field]
Drafted by 10th June 2011; published at DrNMblog.wordpress.com on 7th October 2011