Most economic evaluations in the area of Alzheimer's disease include costs and/or effects related to informal caregiving. However, in other disease areas where informal caregiving is common it seems that the majority of economic evaluations ignore informal caregiving. The inclusion of informal care can have a strong impact on cost-effectiveness outcomes. Future economic evaluations should therefore consider the relevance of informal care in the context of their study, and either include these costs and effects or justify why they were excluded.

Studies that do not include productivity costs may, in many cases, poorly reflect full societal costs (or savings) of an intervention. Furthermore, when comparing total costs reported in studies that include productivity costs, it should be noted that study characteristics such as the methods used to assess productivity costs may affect their level.

Productivity costs can strongly impact cost-effectiveness outcomes. This study investigated the impact in the context of expensive hospital drugs. This study aimed to: (1) investigate the effect of productivity costs on cost-effectiveness outcomes, (2) determine whether economic evaluations of expensive drugs commonly include productivity costs related to paid and unpaid work, and (3) explore potential reasons for excluding productivity costs from the economic evaluation. We conducted a systematic literature review to identify economic evaluations of 33 expensive drugs. We analysed whether evaluations included productivity costs and whether inclusion or exclusion was related to the study population’s age, health and national health economic guidelines. The impact on cost-effectiveness outcomes was assessed in studies that included productivity costs. Of 249 identified economic evaluations of expensive drugs, 22 (9 %) included productivity costs related to paid work. One study included unpaid productivity. Mostly, productivity cost exclusion could not be explained by the study population’s age and health status, but national guidelines appeared influential. Productivity costs proved often highly influential. This study indicates that productivity costs in economic evaluations of expensive hospital drugs are commonly and inconsistently ignored in economic evaluations. This warrants caution in interpreting and comparing the results of these evaluations.Electronic supplementary materialThe online version of this article (doi:10.1007/s10198-015-0685-x) contains supplementary material, which is available to authorized users.