Weight Watchers Successful Part of Diabetes Prevention Program in UK

Becky McCall

October 17, 2017

Patients with prediabetes referred by their general practitioner (GP) to a diabetes prevention program (DPP) that used Weight Watchers, a weight-management program, for the most part avoided developing type 2 diabetes in a UK study.

"National Health Service (NHS) GP referral pathway into a 1-year DPP delivered by [Weight Watchers] achieved statistically significant reductions in measures of type 2 diabetes risk," write Carolyn Piper, department of public health, London, United Kingdom, and colleagues in their paper published online in BMJ Open Diabetes Research and Care.

Of note, with important implications for implementation, they add that their work provides evidence of "how to roll out prevention programs in the real world utilizing existing referral pathways."

Specifically, the program achieved a significant reduction in HbA1c of 2.84 mmol/mol at 12 months, from 43.4 to 40.6 mmol/mol (6.1% to 5.9%; P < .01), and blood glucose levels also returned to normaI in more than a third (38%) of patients, with only 3% developing type 2 diabetes after 12 months. 

This is the first study of a DPP in partnership with Weight Watchers in the UK. A similar US study found that Weight Watchers was effective for achieving lifestyle changes associated with diabetes prevention (Am J Public Health. 2016;106:949-956).

"The lifestyle changes and weight loss achieved in the intervention translated into considerable reductions in diabetes risk, with an immediate and significant public-health impact," write Ms Piper and coauthors.

They point out that evidence indicates that weight-loss interventions provided by commercial weight-management programs are more effective and efficient at achieving weight loss than interventions delivered by primary care alone.

They also remark that data from randomized controlled trials support the fact that "commercial weight-management programs could significantly increase the availability of DPPs."

DPP in Combination With a Weight-Management Program

The researchers aimed to evaluate the effectiveness of a DPP delivered in partnership with Weight Watchers for people with prediabetes referred by UK primary-care services. The current results are the 12-month findings, and the study will have a further 12 months of follow-up.

Fourteen of 25 invited primary-care practices in the Bromley area in London participated. Patients had been diagnosed with nondiabetic hyperglycemia (prediabetes), defined as a fasting plasma glucose of 5.5 to 6.9 mmol/L and/or an HbA1c of 42 to 47 mmol/mol (6.0%–6.4%).

Patients had a body mass index (BMI) ≥ 30 kg/m2, or BMI ≥ 27.5 kg/m2 for those with a comorbidity or of an ethnic minority. Mean weight at baseline was 96.3 kg/m2 and BMI was 35.5 kg/m2. There was a 25%/75% male/female split, 90% were white, and 5% were from the most deprived quintile in the United Kingdom.

The intervention comprised a structured 90-minute activation session on diabetes prevention, which 117 eligible patients attended, with 77% continuing to the standard evidence-based Weight Watchers program for 48 weeks.

The study had two goals: for patients to lose and maintain at least 7% body weight at 12 months and achieve 150 min/week of moderate-intensity physical activity.

Feedback on patient expectations, experiences, and preferences were gathered, and in addition, Bromley Public Health held two patient participation events to reflect on progress and areas for improvement, which will shape the future delivery of the Weight Watchers DPP, write the authors.

Mean Weight Loss of 10 kg Over a Year

Significant mean reductions in weight of 10 kg (22 lb, P < .001) and BMI of 3.2 kg/m2 (P < .001) were observed at 12 months. 

By comparison, a meta-analysis carried out by Public Health England found that the pooled mean weight loss of optimal interventions for prediabetes was 2.5 kg compared with usual care. 

In addition, 54% of patients achieved at least a 7% reduction in body weight at 6 and 12 months, the range in which risk reduction occurs.

Secondary outcomes at 12 months showed an overall improvement in lipid levels, with significant reductions in triglycerides (P < .01) and cholesterol/high-density lipoprotein (HDL) cholesterol ratio (P < .05), and a significant increase in HDL cholesterol in men (P < .05).

Systolic and diastolic blood pressure significantly improved (P < .01), and there was a significant mean reduction in self-reported waist circumference in both men and women (P < .001).

Longer-term Follow-up Needed to See If Benefits Maintained

However, physical activity increased by only 2 min/week (from 111 to 113 min) over 12 months, and program meeting attendance dropped over time, with average attendance of 29 out of 48 sessions over a mean of 40 weeks.

Asked by Medscape Medical News why the change in physical activity was so poor, Ms Piper said that it could be because physical activity is notoriously difficult to measure and was self-reported, with some participants exaggerating their baseline levels of activity so that changes over time didn't appear significant.

And although the mean increase was only 2 min/week, there was a wide variance.

"This shows that some people who adopted exercise really embraced and enjoyed it, but some didn't increase their activity and solely focused on weight loss to reverse diabetes," she said.   

Fasting plasma glucose was significantly reduced at 6 months but not at 12 months, so longer-term follow-up is needed to see if the results will be maintained in the longer term, say the authors.

Ms Piper and coauthors acknowledged that only 5% to 10% of people with prediabetes per year are predicted to progress to type 2 diabetes, with the same proportion converting back to normoglycemia.

Of the 117 patients with prediabetes at baseline, 44 (38%) returned to normoglycemia, 18 (15%) had decreased their risk of type 2 diabetes by reducing their blood glucose, and four (3%) developed type 2 diabetes by 12 months.

The investigators say a randomized trial is needed to measure the effectiveness of different types of referral routes, for example, comparing direct-to-consumer approaches, NHS Health Check referrals, or primary-care referrals.

Further research would also be helpful to determine the optimal patient inclusion criteria for achieving the best results from a DPP, they conclude.

The study was funded by a public-health grant. Weight Watchers provided funding to publish the research article. Ms Piper reported no relevant financial relationships. Disclosures for the coauthors are listed in the paper. 

BMJ Open Diabetes Research and Care. Published online October 16, 2017. Article

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