Do dietary and physical activity interventions in adolescents provide a cost-effective use of healthcare resources? Model development and illustration based on the Engaging Adolescents in Changing Behaviour (EACH-B) programme

Abstract

ABSTRACTObjectiveTo assess costs, health outcomes and cost-effectiveness of interventions that aim to improve quality of diet and level of physical activity in adolescents.DesignA Markov model was developed to assess four potential benefits of healthy behaviour for adolescents: better mental health, Type 2 diabetes, higher earnings and reduced incidences of adverse pregnancy outcomes. The model parameters were informed by published literature. The analysis took a societal perspective over a 20-year period. One-way and probabilistic sensitivity analyses were conducted.SettingSecondary schools.ParticipantsA hypothetical cohort of adolescents aged 12-13 years.InterventionsAn exemplar school-based, multi-component intervention that was developed by the Engaging Adolescents for Changing Behaviour programme, compared with usual schooling.Primary and secondary outcome measuresIncremental cost-effectiveness ratio as measured by cost per quality-adjusted life year (QALY) gained.ResultsThe model suggested that an intervention for improving diet and physical activity has the potential to offer a cost-effective use of healthcare resources for adolescents in the UK at a willingness-to-pay threshold of £20,000 per QALY. The key model drivers are the intervention effect on levels of physical activity, quality of life gain for high levels of physical activity, the duration of the intervention effects and the period over which effects wane.ConclusionsThe model focused on short to medium-term benefits of healthy eating and physical activity exploiting the strong evidence base that exists for this age group. Other benefits in later life, such as reduced cardiovascular risk, are more sensitive to assumptions about the persistence of behavioural change and discounting.ARTICLE SUMMARYStrengths and limitations of this studyThe study addresses an important public health question by examining if interventions targeting healthy eating and doing more physical activities provide value for money from a societal perspective.A Markov cohort model was developed to assess the costs and benefits, expressed in terms of quality-adjusted life years, of an exemplar school-based, multi-component intervention to improve adolescents’ diet and increase their levels of physical activity.The study incorporates existing evidence on the effect of improvement in adolescent health behaviours on four high prevalence short-to-medium term benefits relevant to young people: improved mental health, higher earnings, improved pregnancy outcomes and prevention of Type 2 diabetes.Extensive sensitivity analyses were conducted to investigate the impact of uncertainty over the model assumptions and parameter inputs, thereby highlighting areas where further research would be most useful.A limitation of the study is that it does not estimate the long-term impacts of such interventions due to the lack of longitudinal data on lifetime trajectories of healthy diet and increased levels of physical activity.