van Nooten F E, Koolman X, Busschbach J J V, Brouwer W B F
Institute of Health Policy and Management, Erasmus University Rotterdam, Rotterdam, The Netherlands.
Qual Life Res. 2014 Mar;23(2):377-84. doi: 10.1007/s11136-013-0495-5. Epub 2013 Aug 14.
Time trade-off (TTO) exercises typically present respondents with a limited time horizon, for example 10 years, thus implicitly considerably reducing remaining life expectancy for the average respondent. It is unclear how this affects health state valuations.
The aim of the study is to investigate how awareness of the reduced life span implied by a 10-year TTO affects health state valuations, using an experimental design.
Two Web-based questionnaires (Q1 and Q2) were administered in a sample representative of the Dutch population. Both questionnaires contained three 10-year TTO exercises valuing three distinct health states, specified using the EQ-5D. Q1 used a TTO instruction not explicitly emphasizing the fact that remaining life expectancy was reduced to 10 years, while in Q2 respondents were explicitly made aware of this fact by emphasizing their implied age of death. Respondents answering Q1 were asked retrospectively whether they had been aware of their reduced life span due to the 10-year TTO.
In total, 656 respondents completed the questionnaires (Q1: 339 and Q2: 317). The average age of the respondents was 43 years and 51 % of respondents were male. The average numbers of years traded off for the respondents of Q1 were for TTO1 0.443, TTO2 0.552, and TTO3 2.083 years. For the respondents of Q2, these averages were lower, i.e., TTO1 0.401 (p = 0.085 vs. Q1), TTO2: 0.546 (p = 0.036 vs. Q1), and TTO3: 1.467 years (p = 0.000 vs. Q1). Fifty-seven percent of respondents in Q1 confirmed that they were aware of the reduced life span. This spontaneous awareness had a limited and mixed influence on results. The generalized negative binomial regression analysis, explaining the time traded off showed that age, subjective life expectancy, and questionnaire Q2 (vs. Q1) were negatively associated with the years traded off, whereas education and worse health states in the TTO exercise had a significant positive impact on the years traded off. The probit model investigating the impact on the willingness to trade showed that age (-), education (+), subjective life expectancy (-), questionnaire Q2 versus Q1 (-), the interaction between Q2 and male gender (+), and worse health states in the TTO exercise (+) had a significant impact on the willingness to trade.
These findings emphasize the importance of expected and implied life expectancy in TTOs.
时间权衡（TTO）练习通常会给受访者设定一个有限的时间范围，例如10年，从而含蓄地大幅缩短了普通受访者的剩余预期寿命。目前尚不清楚这对健康状态估值有何影响。
本研究旨在通过实验设计，探究对10年TTO所隐含的寿命缩短的认知如何影响健康状态估值。
在一个具有荷兰人口代表性的样本中实施了两份基于网络的问卷（Q1和Q2）。两份问卷都包含三个10年TTO练习，用于评估三种不同的健康状态，这些状态使用EQ-5D进行了具体描述。Q1使用的TTO说明没有明确强调剩余预期寿命已缩短至10年这一事实，而在Q2中，通过强调受访者隐含的死亡年龄，使其明确知晓这一事实。回答Q1的受访者被回顾性地询问他们是否意识到由于10年TTO导致的寿命缩短。
共有656名受访者完成了问卷（Q1：339人，Q2：317人）。受访者的平均年龄为43岁，51%的受访者为男性。Q1受访者在TTO1中权衡的平均年数为0.443年，TTO2为0.552年，TTO3为2.083年。对于Q2的受访者，这些平均值较低，即TTO1为0.401年（与Q1相比，p = 0.085），TTO2为0.546年（与Q1相比，p = 0.036），TTO3为1.467年（与Q1相比，p = 0.000）。Q1中57%的受访者确认他们意识到了寿命缩短。这种自发的认知对结果的影响有限且好坏参半。解释权衡时间的广义负二项回归分析表明，年龄、主观预期寿命和问卷Q2（与Q1相比）与权衡的年数呈负相关，而教育程度以及TTO练习中较差的健康状态对权衡的年数有显著的正向影响。研究对权衡意愿影响的概率模型表明，年龄（-）、教育程度（+）、主观预期寿命（-）、问卷Q2与Q1相比（-）、Q2与男性性别之间的相互作用（+）以及TTO练习中较差的健康状态（+）对权衡意愿有显著影响。
这些发现强调了TTO中预期和隐含预期寿命的重要性。
