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Study finds extending weight loss programme to be more effective

Referral to a 52-week commercial weight loss programme results in larger and more sustained weight loss than to a 12-week programme and is cost effective, according to new research published in The Lancet.

The findings are from Weight Loss Referrals for Adults in Primary Care (WRAP) trial, a study of overweight or obese adults recruited from general practice in England, led by researchers from the University of Cambridge, University of Liverpool, and University of Oxford.

Obesity greatly increases the risk of chronic diseases such as diabetes, heart disease and some cancers, and the increase in obesity places considerable strain on health care resources. Referral to a commercial group-based weight management programme can help people lose weight, but it is not clear what the optimal duration of the programmes is, and how cost effective they are in the long term.

Chronic condition

In the UK the National Institute for Health and Care Excellence (NICE) recommends that these programmes last at least 12 weeks and in practice, this is the standard referral length. However, obesity is a chronic condition that may require longer treatment.

The researchers recruited 1,267 adults who were overweight or obese from GP practices in England, and randomly allocated them to one of three weight loss programmes: (a) a brief intervention – participants received a booklet of “self-help” strategies that have been shown to help people lose weight on their own; (b) a 12-week group-based programme – participants could go to Weight Watchers for free for 12 weeks; or (c) a 52-week group-based programme – participants could go to Weight Watchers for free for 52 weeks.

At the start of the trial, and again at three months, one year and two years, participants were weighed and other important markers of health risks like blood pressure, waist circumference, fat mass, and blood glucose levels were measured.

Greater reductions

At the end of one year, participants in the 52-week programme had lost 6.8kg, compared to 4.8kg in the 12-week programme, and 3.3 kg in the brief intervention. Compared to participants in the other groups, those in the 52-week programme also had significantly greater reductions in fasting blood glucose and glycosylated haemoglobin, which are important markers of the future risk of developing diabetes.

During the second year of the trial, all groups regained some of the weight lost, but there was still a 1.3 kg difference between those in the 52-week programme and those in the 12-week programme at the two year follow up. In contrast, there was no significant difference between the weight loss in the 12-week programme and the brief intervention groups at the two year follow-up. There was no evidence that the impact of these programmes was affected by gender or socio-economic status.

The researchers then modelled the impact of the three programmes over the next 25 years to predict how many people would develop different weight-related illnesses and what the likely disease progression would be.  They translated the estimated deaths and illnesses into “quality-adjusted life years” or “QALYs”, a metric that values both the length of time people live and the quality of that life. They then added up the cost of the intervention and the costs of treating weight-related illnesses in each group to see which option was the most cost-effective.

Cost-savings

The 12-week programme achieved greater reductions in illnesses than the brief intervention, and cost-savings on NHS treatment of these illnesses outweighed the initial outlay for the cost of the weight loss programme.

The 52-week programme achieved even greater reductions in illnesses than the 12-week programme and resulted in more QALYs. The costs of the 52-week intervention were not outweighed by the cost-savings on NHS treatment of weight-related illnesses, but the cost per QALY gained was only £2,394 compared to the brief intervention, and only £3,804 compared to the 12-week programme. NICE usually consider treatments to be worth funding if the cost per QALY gained is less than about £20,000.

Considerable improvements

Professor Jason Halford, Chair in Biological Psychology and Health Behaviour and Head of the University of Liverpool’s Department of Psychological Sciences, said: “The study provides important information to GPs and NHS treatment commissioners about which treatment option is most effective and which offers best value for money.

“It is clear offering support over a year produces considerable improvements in outcomes which may in the long term provide cost saving to healthcare systems. These results will enable medical professionals to help tackle the obesity problem in a more effective way.

“At Liverpool we were delighted to offer so many the opportunity of access to treatment though this trial and look forward to tracking their progress.”

Lowering diabetes risk

Dr Amy Ahern, a Senior Investigator Scientist from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge, who led the WRAP trial, said: “We’ve seen before that a 12-week programme can help people lose weight, but for the first time we’ve shown that extending this to a full year leads to greater weight loss and lower risk of diabetes.

“Although the initial costs of the year-long programme are greater, it’s very likely that it will be good value for money over the long term because of the reduction in weight-related illnesses. The results from the one-year programme are comparable to what has been seen in previous trials that used much more costly interventions, usually involving multiple contacts with health professionals.”

This research was funded primarily by the National Prevention Research Initiative (a consortium including government departments, research councils and major medical charities).

Weight Watchers International funded the analysis of the blood samples taken as part of the study, as part of an MRC Industrial Collaboration Award. The intervention used was provided free to the NHS by Weight Watchers. The study was conducted by scientists from MRC Human Nutrition Research, University of Cambridge, MRC Biostatistics Unit, University College London, University of Oxford, University of Liverpool, University of East Anglia, University of York, UK Health Forum and London School of Hygiene Tropical Medicine.

The full study, entitled ‘Extended and standard duration weight loss referrals for adults in primary care (WRAP): a pragmatic randomised controlled trial. Lancet’, can be found here.

Source: University of Liverpool

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