title: On discounting of health gains from human papillomavirus vaccination: effects of different approaches.
abstract: OBJECTIVE
  Discounting has long been a matter of controversy in the field of health economic evaluations. How to weigh future health effects has resulted in ongoing discussions. These discussions are imminently relevant for health care interventions with current costs but future benefits. Different approaches to discount health effects have been proposed. In this study, we estimated the impact of different approaches for discounting health benefits of human papillomavirus (HPV) vaccination.
  
  
  METHODS
  An HPV model was used to estimate the impact of different discounting approaches on the present value of health effects. For the constant discount approaches, we varied the discount rate for health effects ranging from 0% to 4%. Next, the impact of relevant alternative discounting approaches was estimated, including hyperbolic, proportional, stepwise, and time-shifted discounting.
  
  
  RESULTS
  The present value of health effects gained through HPV vaccination varied strongly when varying discount rates and approaches. The application of the current Dutch guidelines resulted in a present value of health effects that was eight or two times higher than that produced when using the proportional discounting approach or when using the internationally more common 4% discount rate for health effects, respectively. Obviously, such differences translate into large variations in corresponding incremental cost-effectiveness ratios.
  
  
  CONCLUSIONS
  The exact discount rate and approach chosen in an economic evaluation importantly impact the projected value of health benefits of HPV vaccination. Investigating alternative discounting approaches in health-economic analysis is important, especially for vaccination programs yielding health effects far into the future. Our study underlines the relevance of ongoing discussions on how and at what rates to discount.
authors.affiliation: Department of Medical Microbiology, Molecular Virology Section, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. t.a.westra@umcg.nl
authors.forename: Tjalke A
authors.initials: TA
authors.lastname: Westra
authors.forename: Mehraj
authors.initials: M
authors.lastname: Parouty
authors.forename: Werner B
authors.initials: WB
authors.lastname: Brouwer
authors.forename: Philippe H
authors.initials: PH
authors.lastname: Beutels
authors.forename: Raina M
authors.initials: RM
authors.lastname: Rogoza
authors.forename: Mark H
authors.initials: MH
authors.lastname: Rozenbaum
authors.forename: Toos
authors.initials: T
authors.lastname: Daemen
authors.forename: Jan C
authors.initials: JC
authors.lastname: Wilschut
authors.forename: Cornelis
authors.initials: C
authors.lastname: Boersma
authors.forename: Maarten J
authors.initials: MJ
authors.lastname: Postma
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003362:Cost-Benefit Analysis / Q000379:methods; D005060:Europe; D005260:Female; D006801:Humans; D017589:Immunization Programs / Q000191:economics*; D008875:Middle Aged; D018803:Models, Economic; D030361:Papillomavirus Infections / Q000517:prevention & control*; D057240:Patient Preference / Q000191:economics*; D014481:United States; D002583:Uterine Cervical Neoplasms / Q000517:prevention & control; D055815:Young Adult