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Longer time spent in weight loss programs beneficial, cost-effective

A 52-week open-group behavioral program led to greater weight losses and lower HbA1c levels than a similar 12-week program, and although more expensive, modelling suggests that the 52-week program is cost-effective in the long run, according to research that recently appeared in The Lancet.

Researchers also found that at least 12 weeks of such a program is more effective than brief advice and self-help materials.

“Behavioral weight-management programs are the first-line method to aid weight loss in people who are overweight or obese, and although there is good evidence that some programs can be effective, other programs have not been shown to be effective,” Amy L. Ahern, PhD, MRC Human Nutrition Research, Cambridge, England, and colleagues wrote. “This variation in effectiveness might be due to differences in content and format of interventions, including how long support is provided.”

To gather more data, Ahern and colleagues randomly assigned 211 participants to receive brief advice and self-help materials, 528 participants to a 12-week program and another 528 participants to a 52-week program. All participants were aged 18 and older and had a BMI of 28 kg/m² or greater.

Researchers found that at 1 year, those who received the brief advice and self-help materials had a mean weight loss of 3.26 kg; those in the 12-week program had a mean weight loss of 4.75 kg; and those in the 52-week program had a mean weight loss of 6.76 kg. In addition, participants in the behavioral program lost more weight than those who received brief advice and self-help materials (adjusted difference –2.71 kg;95% CI, –3.86 to –1.55; P < .0001). The 52-week program was more effective than the 12-week program (–2.14 kg; 95% CI, –3.05 to –1.22; P < .0001) and the differences between the groups were still significant at 2 years.

Ahern and colleagues also found that at 12 months, participants in the 52-week program had greater reductions in HbA1c than those in the 12-week program (adjusted difference –1.31 mmol/mol; 95% CI, –2.47 to –0.15, P= .0268) and brief advice and self-help materials (–2.65 mmol/mol; 95% CI, –4.28 to –1.01; P = .0015). Changes over time in BP, HDL, LDL, quality of life, triglycerides, and total cholesterol were small and no significant differences between groups were recorded.

Researchers also found that over 2 years, the incremental cost-effectiveness ratio (compared with receiving brief advice and self-help materials) was 159 per kg lost for the 52-week program and 91 per kg for the 12-week program. Modelled over 25 years after baseline, the incremental cost-effectiveness ratio for the 12-week program was dominant compared with the brief intervention. The incremental cost-effectiveness ratio for the 52-week program was cost-effective compared with the brief intervention (2,394 per quality-adjusted life-year and the 12-week program (3,804 per quality adjusted life-year).

“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,” Ahern said in a press release. “Although the initial costs of the year-long program 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.” – by Janel Miller

Disclosure: Ahern reports receiving research funding to her institution from Weight Watchers International. Please see the study for a full list of the other authors relevant financial disclosures.