Amy L Ahern

Primary care referral to a commercial provider for weight loss treatment versus standard care: a randomised controlled trial

Summary Background The increasing prevalence of overweight and obesity needs effective approaches for weight loss in primary care and community settings. We compared weight loss with standard treatment in primary care with that achieved after referral by the primary care team to a commercial provider in the community. Methods In this parallel group, non-blinded, randomised controlled trial, 772 overweight and obese adults were recruited by primary care practices in Australia, Germany, and the UK. Participants were randomly assigned with a computer-generated simple randomisation sequence to receive either 12 months of standard care as defined by national treatment guidelines, or 12 months of free membership to a commercial programme (Weight Watchers), and followed up for 12 months. The primary outcome was weight change over 12 months. Analysis was by intention to treat (last observation carried forward [LOCF] and baseline observation carried forward [BOCF]) and in the population who completed the 12-month assessment. This trial is registered, number ISRCTN85485463. Findings 377 participants were assigned to the commercial programme, of whom 230 (61%) completed the 12-month assessment; and 395 were assigned to standard care, of whom 214 (54%) completed the 12-month assessment. In all analyses, participants in the commercial programme group lost twice as much weight as did those in the standard care group. Mean weight change at 12 months was −5·06 kg (SE 0·31) for those in the commercial programme versus −2·25 kg (0·21) for those receiving standard care (adjusted difference −2·77 kg, 95% CI −3·50 to −2·03) with LOCF; −4·06 kg (0·31) versus −1·77 kg (0·19; adjusted difference −2·29 kg, −2·99 to −1·58) with BOCF; and −6·65 kg (0·43) versus −3·26 kg (0·33; adjusted difference −3·16 kg, −4·23 to −2·11) for those who completed the 12-month assessment. Participants reported no adverse events related to trial participation. Interpretation Referral by a primary health-care professional to a commercial weight loss programme that provides regular weighing, advice about diet and physical activity, motivation, and group support can offer a clinically useful early intervention for weight management in overweight and obese people that can be delivered at large scale. Funding Weight Watchers International, through a grant to the UK Medical Research Council.

Weight Watchers on prescription: An observational study of weight change among adults referred to Weight Watchers by the NHS

BackgroundThe scale of overweight and obesity in the UK places a considerable burden on the NHS. In some areas the NHS has formed partnerships with commercial companies to offer weight management services, but there has been little evaluation of these schemes.This study is an independent audit of the Weight Watchers NHS Referral scheme and evaluates the weight change of obese and overweight adults referred to Weight Watchers (WW) by the NHS.MethodData was obtained from the WW NHS Referral Scheme database for 29,326 referral courses started after 2nd April 2007 and ending before 6th October 2009 [90% female; median age 49 years (IQR 38 - 61 years); median BMI 35.1 kg/m2 (IQR 31.8 - 39.5 kg/m2). Participants received vouchers (funded by the PCT following referral by a healthcare professional) to attend 12 WW meetings. Body weight was measured at WW meetings and relayed to the central database.ResultsMedian weight change for all referrals was -2.8 kg [IQR -5.9 - -0.7 kg] representing -3.1% initial weight. 33% of all courses resulted in loss of ≥5% initial weight. 54% of courses were completed. Median weight change for those completing a first course was -5.4 kg [IQR -7.8 - -3.1 kg] or -5.6% of initial weight. 57% lost ≥5% initial weight.ConclusionsA third of all patients who were referred to WW through the WW NHS Referral Scheme and started a 12 session course achieved ≥5% weight loss, which is usually associated with clinical benefits. This is the largest audit of NHS referral to a commercial weight loss programme in the UK and results are comparable with other options for weight loss available through primary care.

A within-trial cost-effectiveness analysis of primary care referral to a commercial provider for weight loss treatment, relative to standard care—an international randomised controlled trial

Background:Due to the high prevalence of overweight and obesity there is a need to identify cost-effective approaches for weight loss in primary care and community settings.Objective:We evaluated the cost effectiveness of two weight loss programmes of 1-year duration, either standard care (SC) as defined by national guidelines, or a commercial provider (Weight Watchers) (CP).Design:This analysis was based on a randomised controlled trial of 772 adults (87% female; age 47.4±12.9 years; body mass index 31.4±2.6 kg m−2) recruited by health professionals in primary care in Australia, United Kingdom and Germany. Both a health sector and societal perspective were adopted to calculate the cost per kilogram of weight loss and the ICER, expressed as the cost per quality adjusted life year (QALY).Results:The cost per kilogram of weight loss was USD122, 90 and 180 for the CP in Australia, the United Kingdom and Germany, respectively. For SC the cost was USD138, 151 and 133, respectively. From a health-sector perspective, the ICER for the CP relative to SC was USD18 266, 12 100 and 40 933 for Australia, the United Kingdom and Germany, respectively. Corresponding societal ICER figures were USD31 663, 24 996 and 51 571.Conclusion:The CP was a cost-effective approach from a health funder and societal perspective. Despite participants in the CP group attending two to three times more meetings than the SC group, the CP was still cost effective even including these added patient travel costs. This study indicates that it is cost effective for general practitioners (GPs) to refer overweight and obese patients to a CP, which may be better value than expending public funds on GP visits to manage this problem.

The challenge of a 2-year follow-up after intervention for weight loss in primary care

Background:Many weight loss programmes show short-term success, but long-term data in larger studies are scarce, especially in community settings. Attrition is common and complicates the interpretation of long-term outcomes.Objective:To investigate 2-year outcomes and explore issues of attrition and missing data.Subjects:A total of 772 overweight and obese adults recruited by primary care practices in Australia, Germany and the UK and randomised to a 12-month weight loss intervention delivered in a commercial programme (CP) or in standard care (SC).Measurement:Weight change from 0–24 and 12–24 months including measured weights only and measured and self-reported weights, using last observation carried forward (LOCF), baseline observation carried forward (BOCF), completers-only and missing-at-random (MAR) analyses.Results:A total of 203 participants completed the 24-month visit. Using measured weights only, there was a trend for greater 24-month weight loss in CP than in SC, but the difference was only statistically significant in the LOCF and BOCF analyses: LOCF: −4.14 vs −1.99 kg, difference adjusted for centre −2.08 kg, P<0.001; BOCF: −1.33 vs −0.74 kg, adjusted difference −0.60 kg, P=0.032; completers: −4.76 vs −2.99 kg, adjusted difference −1.53 kg, P=0.113; missing at random: −3.00 vs −1.94 kg, adjusted difference −1.04 kg, P=0.150. Both groups gained weight from 12–24 months and weight regain was significantly (P<0.001) greater for CP than for SC in all analysis approaches. Inclusion of self-reported weights from a further 138 participants did not change the interpretation of the findings.Conclusion:Initial weight loss was poorly maintained during the no-intervention follow-up, but both groups did have lower weight over the 24 months. Attrition was high in both groups, and assumptions about missing data had considerable impact on the magnitude and statistical significance of treatment effects. It is vital that trials on weight loss interventions consider the plausibility of these differences in an analytical approach when interpreting research findings and comparing data between studies.

Participants’ explanatory model of being overweight and their experiences of 2 weight loss interventions

PURPOSE We explored participants’ accounts of weight loss interventions to illuminate the reasons behind the greater weight loss observed among those attending a commercial program compared with those receiving standard care in a recent large-scale trial. We further wanted to examine how participants’ general explanatory model of being overweight related to the 2 different interventions. METHODS Our study was based on thematic analysis of semistructured telephone interviews with a purposeful sample of 16 female participants from the UK center of a randomized controlled trial of weight loss in primary care. RESULTS The commercial provider delivered weight management in a nonmedical context, which mirrors how participants regard being overweight. Participants felt they needed support and motivation rather than education, and valued the ease of access and frequent contact the commercial provider offered. Some participants preferred individual level support with their primary care clinician, and all were positive about the opportunity to access support through the primary care setting. CONCLUSIONS Primary care referral to a commercial weight loss program for people who do not require specific clinical care appears to be in accord with their general explanatory model about being overweight, offering motivation and support to lose weight outside a strictly medical context. This approach may not be effective or acceptable for everyone, however, and there are likely to be considerable variations in the explanatory models held. Findings support the argument that a range of evidence-based options for weight management should be available in primary care.

Extended and standard duration weight-loss programme referrals for adults in primary care (WRAP): a randomised controlled trial

Summary Background Evidence exist that primary care referral to an open-group behavioural programme is an effective strategy for management of obesity, but little evidence on optimal intervention duration is available. We aimed to establish whether 52-week referral to an open-group weight-management programme would achieve greater weight loss and improvements in a range of health outcomes and be more cost-effective than the current practice of 12-week referrals. Methods In this non-blinded, parallel-group, randomised controlled trial, we recruited participants who were aged 18 years or older and had body-mass index (BMI) of 28 kg/m2 or higher from 23 primary care practices in England. Participants were randomly assigned (2:5:5) to brief advice and self-help materials, a weight-management programme (Weight Watchers) for 12 weeks, or the same weight-management programme for 52 weeks. We followed-up participants over 2 years. The primary outcome was weight at 1 year of follow-up, analysed with mixed-effects models according to intention-to-treat principles and adjusted for centre and baseline weight. In a hierarchical closed-testing procedure, we compared combined behavioural programme arms with brief intervention, then compared the 12-week programme and 52-week programme. We did a within-trial cost-effectiveness analysis using person-level data and modelled outcomes over a 25-year time horizon using microsimulation. This study is registered with Current Controlled Trials, number ISRCTN82857232. Findings Between Oct 18, 2012, and Feb 10, 2014, we enrolled 1269 participants. 1267 eligible participants were randomly assigned to the brief intervention (n=211), the 12-week programme (n=528), and the 52-week programme (n=528). Two participants in the 12-week programme had been found to be ineligible shortly after randomisation and were excluded from the analysis. 823 (65%) of 1267 participants completed an assessment at 1 year and 856 (68%) participants at 2 years. All eligible participants were included in the analyses. At 1 year, mean weight changes in the groups were −3·26 kg (brief intervention), −4·75 kg (12-week programme), and −6·76 kg (52-week programme). Participants in the behavioural programme lost more weight than those in the brief intervention (adjusted difference −2·71 kg, 95% CI −3·86 to −1·55; p<0·0001). The 52-week programme was more effective than the 12-week programme (−2·14 kg, −3·05 to −1·22; p<0·0001). Differences between groups were still significant at 2 years. No adverse events related to the intervention were reported. Over 2 years, the incremental cost-effectiveness ratio (ICER; compared with brief intervention) was £159 per kg lost for the 52-week programme and £91 per kg for the 12-week programme. Modelled over 25 years after baseline, the ICER for the 12-week programme was dominant compared with the brief intervention. The ICER for the 52-week programme was cost-effective compared with the brief intervention (£2394 per quality-adjusted life-year [QALY]) and the 12-week programme (£3804 per QALY). Interpretation For adults with overweight or obesity, referral to this open-group behavioural weight-loss programme for at least 12 weeks is more effective than brief advice and self-help materials. A 52-week programme produces greater weight loss and other clinical benefits than a 12-week programme and, although it costs more, modelling suggests that the 52-week programme is cost-effective in the longer term. Funding National Prevention Research Initiative, Weight Watchers International (as part of an UK Medical Research Council Industrial Collaboration Award).

Personal and social norms for food portion sizes in lean and obese adults

Background:Portion size is an important component of dietary advice for weight control, but little is known about what portion sizes people consider ‘normal’. This study determined the effect of body mass index (BMI), gender, dietary restraint and liking of the food on personal and social portion size norms for a range of foods and the degree of certainty over the norms.Methods:Thirty lean (BMI 20–25 kg m−2) and 30 obese (BMI 30–35 kg m−2) men and women (aged 18–60 years) viewed 17 different portion sizes of 12 foods on a computer screen on two occasions a week apart. Participants responded ‘more’ or ‘less’ to each photograph reflecting personal portion size preference or perceived portion sizes of others. Personal and social norms for portion sizes of each food were determined using the method of constant stimuli giving a sigmoidal curve of the probability of answering ‘less’ over a range of portion sizes. The slope of the sigmoid at the norm gave a measure of certainty about the norm. Regression models were used to examine the effect of BMI, gender, dietary restraint and liking of the food on personal norms, social norms, the relationship between norms, and the slopes.Results:Personal norms were significantly larger in the obese (P=0.026), men (P<0.001), those with lower dietary restraint (P<0.001), and those with higher liking for the food (P<0.001). Social norms were larger for women (P=0.012). The slopes at the norms were 30% shallower in the obese and in men (P<0.001).Conclusion:Larger personal norms for portion size among the obese, men, those with lower dietary restraint and those with higher liking for a food imply greater consumption, which may undermine weight control. Shallower slopes for norms in the obese and in men may imply less clearly defined habitual portion sizes.

Inequalities in the uptake of weight management interventions in a pragmatic trial: an observational study in primary care

Background Primary care referral to a commercial open-group behavioural weight-loss programme is a cost-effective intervention, but only 10% of patients receiving this intervention are male. Aim To explore whether observed biases in participation in these interventions reflect biases in the uptake of the invitation to participate. Design and setting Comparison of invited population and recruited participants in a multicentre randomised controlled trial of primary care referral to a commercial open-group behavioural weight-loss programme in England (WRAP [Weight loss Referrals for Adults in Primary care]). Method Between October 2012 and February 2014, participants were recruited through 23 primary care practices in England; 17 practices provided data on the characteristics of invited participants. Results Females were twice as likely as males to enrol in the trial (odds ratio [OR] 2.01, 95% confidence interval [CI] = 1.75 to 2.32). However, the proportion of males was threefold higher than seen in routine primary care referrals or similar trials that invited patients opportunistically. People from less deprived areas were more likely to enrol than those in more deprived areas (OR 1.77, 95% CI = 1.55 to 2.03). Older patients (≥40 years) were more likely to enrol than younger patients (OR 1.60, 95% CI = 1.34 to 1.91). Conclusion Males, younger people, and those from more deprived areas were less likely to take up the invitation to participate in this trial. The gender bias was smaller than observed in routine practice, suggesting that a substantial proportion of the inequity observed previously is a consequence of bias with regard to the offer of intervention. This study suggests that a simple way to overcome much of the gender bias is to write to patients who are overweight and offer referral. Uptake of the invitation to participate was lower in groups of lower socioeconomic status suggesting the need to preferentially offer referrals to this group to reduce health inequalities and for research to explore barriers to uptake.

How much should I eat? A comparison of suggested portion sizes in the UK.

Objective To identify and compare suggested food portion sizes in UK schemes. Design The study collated and compared suggested portion sizes from selected UK schemes intended both for general advice and weight-loss advice. Setting Portion size schemes were included if they were relevant to the UK, provided actual portion size information, were intended for adults and were obtainable from the public domain in November 2010. Included schemes were from the food industry, non-governmental organisations and health-care professionals. Suggested portion sizes of foods occurring in at least one scheme for general advice and at least one scheme for weight loss were included. Own brand on-pack portion size labelling from a large UK-wide supermarket was added to represent portion size advice from UK food retailers. Subjects Not applicable. Results The suggested portion sizes in the weight-loss advice schemes were often concordant, as were the general advice schemes, except one general advice scheme from a non-governmental organisation which was more closely aligned with the portion sizes for weight loss. Overall there were substantial discrepancies between suggested portion sizes for muesli and crunchy breakfast cereals, rice, pasta and potatoes, meat, fish and pulses, whereas portion sizes for cooked vegetables, dried fruit, some breakfast cereals and cheese were broadly consistent. Conclusions There is a lack of consistency in the portion sizes communicated to the public. An independent and authoritative scheme of suggested portion sizes for all foods, with distinct recommendations for general advice and for weight-loss advice, could be of benefit.

The Presence of Real Food Usurps Hypothetical Health Value Judgment in Overweight People.

Abstract To develop more ecologically valid models of the neurobiology of obesity, it is critical to determine how the neural processes involved in food-related decision-making translate into real-world eating behaviors. We examined the relationship between goal-directed valuations of food images in the MRI scanner and food consumption at a subsequent ad libitum buffet meal. We observed that 23 lean and 40 overweight human participants showed similar patterns of value-based neural responses to health and taste attributes of foods. In both groups, these value-based responses in the ventromedial PFC were predictive of subsequent consumption at the buffet. However, overweight participants consumed a greater proportion of unhealthy foods. This was not predicted by in-scanner choices or neural response. Moreover, in overweight participants alone, impulsivity scores predicted greater consumption of unhealthy foods. Overall, our findings suggest that, while the hypothetical valuation of the health of foods is predictive of eating behavior in both lean and overweight people, it is only the real-world food choices that clearly distinguish them.