title: Quality of life and time to death: have the health gains of preventive interventions been underestimated?
abstract: This article explores the implications of the relation between quality of life (QoL) and time to death (TTD) for economic evaluations of preventive interventions. By using health survey data on QoL for the general Dutch population linked to the mortality registry, we quantify the magnitude of this relationship. For addressing specific features of the nonstandard QoL distribution such as boundness, skewness, and heteroscedasticity, we modeled QoL using a generalized additive model for location, scale, and shape (GAMLSS) with a β inflated outcome distribution. Our empirical results indicate that QoL decreases when approaching death, suggesting that there is a strong relationship between TTD and QoL. Predictions of different regression models revealed that ignoring this relationship results in an underestimation of the quality-adjusted life year (QALY) gains for preventive interventions. The underestimation ranged between 3% and 7% and depended on age, the number of years gained from the intervention, and the discount rate used.
authors.affiliation: Institute of Health Policy and Management/Institute of Health Technology Assessment Erasmus University Rotterdam, the Netherlands.
authors.forename: Maria
authors.initials: M
authors.lastname: Gheorghe
authors.affiliation: Institute of Health Policy and Management/Institute of Health Technology Assessment Erasmus University Rotterdam, the Netherlands.
authors.forename: Werner B F
authors.initials: WB
authors.lastname: Brouwer
authors.affiliation: Institute of Health Policy and Management/Institute of Health Technology Assessment Erasmus University Rotterdam, the Netherlands.
authors.forename: Pieter H M
authors.initials: PH
authors.lastname: van Baal
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001294:Attitude to Health; D003362:Cost-Benefit Analysis; D003643:Death; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009426:Netherlands; D017063:Outcome Assessment, Health Care; D011788:Quality of Life; D019057:Quality-Adjusted Life Years; D012737:Sex Factors; D013997:Time Factors
keywords: GAMLSS; QALYs; prevention; quality of life; time to death; β inflated distribution