Extending Weight Loss Programs Cost Effective Way of Preventing Diseases, UK Study Finds

05 May 2017 --- A UK study has found that extending NHS weight loss programs from one session per week for 12-weeks to one session per week for a year helped people who are overweight to lose more weight and keep it off for longer. Although upfront costs for the longer program are higher, the study estimates that offering more sessions would be cost-effective to the NHS in the long-term because it would help to prevent more people from developing diseases as a result of their weight.

"This trial provides important data that offering support to lose weight - by referring people to a community weight loss group - is more successful than a self-help approach and that providing classes for longer helps people keep weight off for longer," says Professor Susan Jebb, senior author of the study, University of Oxford, UK.

The NHS currently refers people who are obese to 12-week long weight loss programs run by commercial groups and provides vouchers for free attendance. These are among the most commonly commissioned programs to treat obesity in the UK and the National Institute for Health and Care Excellence recommends that programs last at least 12 weeks. However, there is little evidence to suggest how long these programs should last to be most effective.

The new study involves 1267 participants with a BMI of 28 or above and compares the effectiveness of a 12-week and year-long program of free Weight Watchers sessions to one-off advice together with a self-help booklet.

After a year, those given the self-help booklet had lost 3.3kg, those referred to the 12-week program had lost 4.8 kg, and those referred to the year-long program had lost 6.8kg on average. Two years after they began treatment, participants in all groups regained some weight, but all groups were still lighter on average than at the start of treatment. The self-help group were 2.3kg lighter, the 12-week program was 3.0kg lighter, while those in the group offered a one-year program were 4.3kg lighter.

Compared to participants in the other groups, those in the year-long program also had significantly greater reductions in fasting blood glucose and glycosylated hemoglobin, which are important markers of the risk of developing diabetes. After a year, those on the year-long program saw their blood glucose level reduce by 0.54mmol per liter of blood (compared to reductions of 0.27mmol/liter for the 12-week group and 0.11mmol/liter for the self-help group).

The researchers also modeled the impact of the three programs over the next 25 years to predict how many people would develop different weight-related illnesses. They also estimated the impact of the programs on quality of life, the cost of providing the programs, as well as cost-savings to health services from preventing future diseases.

The 12-week program was predicted to prevent more illnesses than the self-help intervention due to greater weight loss. Over 25 years, the cost to the NHS of providing the program would be more than offset by the later savings as a result of reductions in disease, making it overall cost-saving.

Offering a year-long program was estimated to prevent an additional 1786 cases of disease (including 642 fewer cases of hypertension, 373 fewer cases of diabetes and 104 fewer cases of heart disease) for every 100,000 people, compared to the 12-week program. So, although it was more expensive upfront, the study shows that the year-long program is cost-effective over 25 years by preventing more cases of weight related illness.

"We've seen before that a 12-week program 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 over a longer period and a lower risk of diabetes," says lead author Dr Amy Ahern, MRC Epidemiology Unit at The University of Cambridge, UK. 

The researchers note some limitations of their study, including that the projections do not include potential savings in social care. Program costs may be overestimated because they assumed all participants who attended at least one session where charged at a flat rate, as opposed to a charge per session attended. In reality, the study found that those in the 12-week program attended eight of 12 sessions on average, and those on the year-long course attended 28 of 52 sessions. During the study, all participants were able to use other weight loss methods, with one in 20 people assigned to self-help attending weight loss sessions, and one in five people on the 12-week program paying to continue to take part in the program at one year.

The study was led by researchers from the University of Cambridge, University of Liverpool and University of Oxford and published online in The Lancet on May 3. The study was funded by the National Prevention Research Initiative (a consortium including government departments, research councils and major medical charities). The analysis of the blood samples taken as part of the study was funded by Weight Watchers International, as part of an MRC Industrial Collaboration Award.