This study was based on a single randomised controlled trial (RCT) and had a time horizon of 12 months. The authors reported that the perspective was societal.
The economic study was based on a single RCT, in which the patients were identified from primary care practices in Leeds and assigned to either the internet-based intervention or to usual care, using a computer-generated randomisation procedure. Due to the nature of the study, it was not possible for the patients or researchers to be blinded to the allocation. A total of 111 patients were allocated to the intervention and 110 to usual care. At six months, 42 patients in the intervention group and 27 in the usual care group were lost to follow-up and at 12 months, a further 15 patients in the intervention group and a further six in the usual care group were lost to follow-up. The main clinical effectiveness estimate was the ability of the internet-based intervention to promote changes in weight and body mass index (BMI) over six and 12 months compared with usual care.
Monetary benefit and utility valuations:
The quality of life estimates were derived from the European Quality of life (EQ-5D) questionnaire, which patients were asked to complete at baseline, six and 12 months.
Measure of benefit:
Quality-adjusted life-years (QALYs) gained were the measure of benefit.
The authors did not provide a comprehensive list of the cost categories. They reported that the costs of introducing the internet website-based intervention were included, and the costs for general practitioners and practice nurses were derived from the Personal Social Services Research Unit. All costs were reported in UK pounds sterling (£) and discounting was not needed, given the short time horizon.
Analysis of uncertainty:
The uncertainty was investigated using cost-effectiveness acceptability curves (CEAC), which showed the proportion of simulations, produced using an econometric model, in which the web-based intervention was more cost-effective, over a range of alternative thresholds or willingness to pay for additional QALY gained.