This study will recruit participants from within General Practice (GP) surgeries in the Leeds (UK) area. Posters will be placed in participating GP practices, advertising the study and asking interested potential participants to call the study centre or to inform their General Practitioner (GP) or practice nurse of their interest. Potential participants will then be screened for eligibility to participate.
BMI >30 kg/m2
18–65 years of age (due to body composition changes over the age of 65 years)
Able to access the Internet at least once per week
Able to read and write in English (for the purposes of accessing the site and completing questionnaires)
Pregnant or lactating women
Women planning on becoming pregnant within the next year
Any illness or reason where the GP feels that the patient should not be taking part in a clinical trial.
With 180 participants in total we should be able to detect a difference of 5 kg weight loss (approximately 5% of body weight) or less than 2.5 kg/m2 in BMI between the two groups with 80% power. This assumes a two-sample t-test, 5% significance levels, a standard deviation for weight of 12 kg and for BMI of 5.5 kg/m2. An additional 22% of participants will be recruited to take account of any loss to follow-up, giving a target recruitment figure of 220.
Eligible participants will be sent a covering letter, participant information sheet, consent form and an initial approach questionnaire. Consenting participants will be contacted by telephone to arrange a first visit with the research team at their GP surgery. At the first visit height, weight, waist and hip circumference will be measured for each participant. The baseline questionnaire will then be administered. At this point the participant will be randomly allocated using minimisation (Minim) into either the treatment group or the usual care group. Because of the nature of the intervention, it is not possible to blind either the participants or the researchers to the group assignment. Participants will be followed-up 6 months and 12 months after randomisation. At these visits they will have their height, weight, waist and hip measurements repeated, and will be asked to complete a further questionnaire at each visit.
The UK weight control site will provide free weight management information based on the best possible advice from experts in the field. It will enable patients to manage their own care and to vary the frequency of use according to their own needs. The site will offer personalised advice to participants, which, in the context of the Internet, involves targeting the information provided to an individual based on their responses to a series of online questions. This will enable targeted motivational statements to be generated to participants whenever they visit the site. In addition, details of progress in terms of self-reported weight loss will be stored on the site, accessible only to the individual concerned. Participants will be given a demonstration of the website and its services, along with a username and password to access the site. They will be encouraged to log on frequently over the first few days in order to get accustomed to the site. After that participants will be encouraged to visit the site as often as they wish. Site usage will be monitored, along with the nature of participant queries and the time spent in dealing with them. Automatic emails will be generated if participants do not visit the site regularly to encourage them to visit more often.
'Usual Care' Group
Participants randomised to this group will be advised to continue with their usual approach to weight loss, e.g. to contact their GP, obtain a dietetic referral, or visit commercial slimming clubs. Participants will be given a small amount of printed information to prevent 'resentful demoralisation'. This will be developed to reflect the type of information available both within the primary care setting and featured on the website.
Data will be analysed using SPSS. Differences in the primary outcome (change in BMI) and secondary outcomes will be compared using t-tests for continuous variables and chi-squared tests for categorical variables. Where continuous variables are not normally distributed, appropriate non-parametric statistical tests will be employed.
The primary outcome will be the ability of the Internet package to promote change in BMI over 6 and 12 months compared with traditional treatment. Secondary outcomes will be the ability of the Internet package to promote change in reported lifestyle behaviours compared with traditional treatment. In addition, data will be collected on participant preferences, adherence to treatment, health care use and time off work. Difference in cost between groups in provision of the intervention and the cost of the primary outcome will also be estimated. The outcome of the trial will be known in April 2005.
Confidentiality and anonymity
Participants will be identified through the use of an identification number only. No possible identifiers will appear on any publicly accessible documentation. Data will be stored in locked filing cabinets and contact details will be stored separately to identification numbers.
Relevance to clinical practice
A positive result would enhance the repertoire of treatment approaches available for the management of obesity. A negative result would be used to inform the research agenda and contribute to redefining future strategies for tackling obesity.