[Cost-effectiveness: euros per QALY is not enough].

: The number of economic evaluations being published in scientific literature each year is increasing exponentially. Cost-effectiveness seems to be playing an increasing role in decisions about reimbursement or the implementation of curative or preventive interventions. A cost-effectiveness ratio represents the fraction between the costs and effects that are associated with an intervention. What costs are included in the numerator of the fraction? What assumptions on effectiveness and reach are made to express the denominator? Various examples have shown that small differences in assumptions can have significant consequences for the cost-effectiveness ratio. This holds true for presumptions on the long-term effects of an intervention as well as the willingness to participate in an intervention. Such assumptions and choices can sometimes highly determine the outcome of a cost-effectiveness analysis. For this reason, caution in interpreting results of cost-effectiveness analyses is warranted.