Implications for practice and research

• ■ Generalist nurses (eg, practice nurses) can contribute to the social support element of weight loss interventions to improve participation and adherence.

• ■ Coaching patients within weight loss interventions (in person or remotely by email or phone) requires further specialist training in motivational interviewing and weight management.

• ■ Establishing which elements (within a complex programme) are effective in specific contexts would be useful to refine nursing practice in weight management.

Context

Obesity prevalence trends are a public health concern in many parts of the world. Excess body fat is linked to adverse health outcomes.1 Evidence-based guidelines recommend multi-component interventions that include behavioural and lifestyle change.2 ,3 Primary care nursing is a key site for provision of and referral on to weight loss interventions. However, while the efficacy of lifestyle and behavioural interventions in clinical trials is established, less is known of patient's adherence and outcomes in routine practice.4

Appel et al describe a trial in which two multi-component lifestyle interventions were compared and evaluated against a control, within routine primary care practice in Baltimore, USA.

Findings

Of 1370 individuals registering at the study website, 415 were randomised. Overall, the mean age was 54 years. The majority were women (63.6%). Based on the participants' ethnicity, a total of 56.1% were White, 41% were Black and <5% were Asian, Hispanic and other groups. A majority were college graduates (59.3%) and employed (75.2%). Only about a fifth (21.9%) had a household income below $50 000. Most (86.7%) of them were daily users of the internet. Mean body mass index at baseline was 36.6.

The primary outcome was weight loss with measures at 6, 12 and 24 months (94.5% follow-up). All groups lost weight: −0.8 kg for the control group; −4.6 kg for the remote support group; and −5.1 kg for the in person support group. The intervention group changes in comparison to control were statistically significant at the p<0.001 level but not in comparison with each other.

The study examined participation rates in the intervention groups. The intensity of support required by participants reduced over time for both groups with the in person group apparently preferring the more flexible remote methods (telephone, email and web pages).

Commentary

This was a high-quality pragmatic trial with good applicability to clinical practice. It adds to the evidence that multi-component interventions help people to lose weight.3 ,4 The study demonstrates this can be achieved in a primary care context with weight improvement sustained over 2 years. It also adds evidence about how web-based resources and remote support can be employed.

However, with complex interventions it is difficult to identify which elements worked in which contexts. The trial interventions were comprehensive and well resourced. In particular, the quality of the web resources and coaching could not be reproduced in routine primary care without considerable set-up costs.

A limitation of the study is a bias towards people who were better off and computer literate. The findings are valuable in demonstrating high participation and long-term benefits for this group. Conversely, it adds little to evidence about how low-income groups (who suffer more of the ill-health consequences of obesity) might effectively manage weight.2