Lifestyle intervention: from cost savings to value for money.

Prevention of unhealthy lifestyles has sometimes been promoted as simultaneously reducing costs and improving public health but this will unlikely prove to be true. Additional medical costs in life years gained due to treatment of unrelated diseases may offset possible savings in related diseases, but are often ignored both in health promotion policies and in economic evaluations of life-prolonging interventions. Many national guidelines explicitly recommend excluding these costs from economic evaluations or leave inclusion up to the discretion of the analyst. This may result in too favorable estimations of cost-effectiveness, feeding the unjustified optimism among policymakers regarding lifestyle interventions as a cost-saving option. However, prevention may still be a cost-effective way to improve public health, even when it does not result in cost savings, but this should be judged taking all future costs into account and be based on the true value for money provided by lifestyle interventions.