What challenges exist in assessing the value of prevention in healthy patients?
Assessing the value of prevention in healthy patients is generally more difficult than evaluating therapy for established disease because the time horizon to the clinical manifestation of disease is generally long, often many decades in the young. This makes it difficult, if not impossible, to assess long-term effectiveness in terms of survival or quality-adjusted life-years (QALYs) or associated costs due to increasing uncertainty about outcome the further one tries to look into the future. Furthermore, the principle of discounting, which places relative emphasis on current costs and benefits while deemphasizing downstream costs and benefits, creates disadvantages for prevention because costs often accrue in the present while the benefit may only be fully realized long into the future. These methodological challenges must be taken into consideration when assessing the value of prevention in healthy patients. 