Future Offspring Costs in Economic Evaluation.

Economic evaluation guidelines increasingly prescribe inclusion of all future costs. We point at an important dimension of future costs that is systematically neglected. Healthcare can affect future offspring, either through affecting the patient's fertility or through determining future offspring's health. As we show, the future costs associated with these changes can be substantial and will vary across interventions and demographic groups. However, systematic inclusion of these future offspring costs would raise many problems on its own. Based on the population ethics concept of necessitarianism, we suggest that only those future costs that spring from 'necessary' future lives should be included in future cost calculations, while all costs associated with 'potential' future lives can be ignored. This approach allows excluding most future offspring costs and avoids skewed cost-effectiveness outcomes of interventions with fertility effects, while taking into account the economic implications of preventing disease in future generations that will exist by necessity. Overall, future generations expose a substantial gap in today's Health Technology Assessment (HTA) methodology and further discussion of the issues they raise is needed.