Comparative effectiveness of weight-loss interventions in clinical practice

The worldwide public health problem of obesity

Dr Geoff Chadwick, Consultant Physician, St Columcille’s Hospital, Dublin

January 1, 2012

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  • Obesity is an important and growing public health problem around the world. In the US, approximately one-third of adults are obese. Obesity adversely affects each of the major cardiovascular risk factors – blood pressure, lipid profile and diabetes. As a consequence, obese people have an increased risk of death, especially from cardiovascular disease. The economic burden of the obesity epidemic is enormous; the estimated direct and indirect costs related to obesity exceed $110 billion annually in the US.

    An extensive body of evidence from efficacy trials has shown that weight loss is achievable and that modest weight loss has beneficial effects on cardiovascular risk factors. However, virtually all these trials tested intensive in-person interventions in highly selected participants. Typically, primary care providers (PCPs) were not directly involved in the intervention. 

    Few weight-loss trials have examined the effect of behavioural interventions in clinical practice, and the results of these trials have been inconsistent. Consequently, even though it is recommended that clinicians offer intensive counselling and behavioural support to their obese patients, practising physicians lack effective, empirically supported models of treatment to guide their efforts in helping obese patients to lose weight.

    To address the need for treatment models, these authors from Johns Hopkins University, Baltimore, US, conducted a randomised, controlled trial to determine the effectiveness of two behavioural weight-loss interventions – including one without in-person contact – in obese patients with at least one cardiovascular risk factor. 

    The intervention without in-person contact provided patients with support by phone, the internet and e-mail. The other intervention offered these remote sources of support but reflected common practice in efficacy trials by also providing face-to-face group and individual sessions conducted by health coaches. 

    Participants in the control group received brief advice, but none of the above resources. It was anticipated that patients assigned to both active interventions would achieve greater weight loss than those in the control group; and that patients in the group receiving in-person support would achieve greater weight loss than those in the group receiving only remote support.

    Participants were recruited from six primary care practices: 63.6% were women, 41.0% were black, and the mean age was 54.0 years. One intervention provided patients with weight-loss support remotely – through the phone, a study-specific website and e-mail. 

    The other intervention provided in-person support during group and individual sessions, along with the three remote means of support. 

    There was also a control group in which weight loss was self-directed. 

    Outcomes were compared between each intervention group and the control group and between the two intervention groups. For both interventions, primary care providers reinforced participation at routinely scheduled visits. The trial duration was 24 months.

    At baseline, the mean body mass index (the weight in kilograms divided by the square of the height in metres) for all participants was 36.6, and the mean weight was 103.8kg. 

    At 24 months, the mean change in weight from baseline was −0.8kg in the control group, −4.6kg in the group receiving remote support only (p < 0.001 for the comparison with the control group), and −5.1kg in the group receiving in-person support (p < 0.001 for the comparison with the control group). 

    The percentage of participants who lost 5% or more of their initial weight was:

    • 18.8% in the control group
    • 38.2% in the group receiving remote support only
    • 41.4% in the group receiving in-person support. 

    The change in weight from baseline did not differ significantly between the two intervention groups.

    In two behavioural interventions, one delivered with in-person support and the other delivered remotely, without face-to-face contact between participants and weight-loss coaches, obese patients achieved and sustained clinically significant weight loss over 24 months.

    1. Appel LJ, Clark JM, Yeh HC et al, N Engl J Med 2011; 365: 1959-1968
    © Medmedia Publications/Hospital Doctor of Ireland 2012