背景:在EQ-5D-5L仪器的估值研究中,复合时间权衡方法(cTTO)通常用于引出偏好。在cTTO中,一些健康状况被认为比死亡更糟糕(WTD),并被赋予负效用值。然而,这些负值与状态严重程度相关性差,这表明cTTO不够敏感。最近的阈值解释已被提供,以解释缺乏相关性:因为超过一个状态被认为是WTD的严重程度阈值在受访者之间不同,应针对按WTD州数量聚集的个体受访者进行相关性研究。在这种阈值方法中获得的结果被解释为反驳了cTTO方法的不敏感性。
目的:仔细检查阈值解释并测试它是否确实反驳了cTTO的不敏感性。
方法:该研究使用EQ-5D-5L波兰估值研究的数据,其中包括来自1,510名参与者的CTTO回复,每个人评估10个EQ-5D-5L状态。重复相关性分析和阈值方法以确认先前研究的结果。然后以两种对比方式修改数据。首先,负面实用程序被随机改组,以测试阈值方法是否可以捕获cTTO不敏感性。第二,个体水平的回归用于模拟负值,以确保它们与个体应答者水平的严重程度相关,验证是否应观察总体严重性-效用相关性。
结果:首先,重新调整负效用不会改变阈值方法的结果。因此,阈值解释未能证明CTTO敏感性。第二,当在个人层面引入敏感性时,严重程度和负效用之间存在显著的总体相关性。
结论:cTTO对WTD状态的严重程度不敏感。
结论:对于复合时间权衡方法,健康状况比死亡更糟糕的效用值与状态严重程度的相关性较差,这表明cTTO灵敏度不足。最近,对缺乏相关性提供了所谓的阈值解释。我说明了为什么阈值解释失败,以及为什么复合时间权衡对于比死亡更差的状态确实不敏感。
In valuation studies of the EQ-5D-5L instrument, the composite time tradeoff method (cTTO) is often used to elicit preferences. In cTTO, some health states are considered worse than dead (WTD) and are assigned negative utility values. However, these negative values correlate poorly with state severity, which suggests that cTTO is insufficiently sensitive. A recent threshold explanation has been offered to account for the lack of correlation: because the severity threshold beyond which a state is considered WTD differs between respondents, the correlation should be studied for individual respondents clustered by the number of WTD states. The results obtained in such a threshold approach were interpreted to disprove the insensitivity of the cTTO method.
To scrutinize the threshold explanation and test whether it indeed refutes the insensitivity of cTTO.
The study uses data from the EQ-5D-5L Polish valuation study, which includes cTTO responses from 1,510 participants, each of whom evaluated 10 EQ-5D-5L states. The correlation analysis and threshold approach are repeated to confirm the results from previous studies. The data are then modified in 2 contrasting ways. First, negative utilities are randomly reshuffled to test whether the threshold approach can capture cTTO insensitivity. Second, individual-level regressions are used to simulate negative values to ensure they correlate with severity at the individual respondent level, verifying whether the overall severity-utility correlation should be observed.
First, reshuffling negative utilities does not change the results of the threshold approach. Hence, the threshold explanation fails to prove cTTO sensitivity. Second, when sensitivity was introduced on an individual level, a significant overall correlation between severity and negative utility arose.
cTTO is insensitive to severity for WTD states.
For the composite time tradeoff method, the utility values of health states worse than dead correlate poorly with state severity, which suggests that cTTO has insufficient sensitivity.Recently, a so-called threshold explanation was offered for the lack of correlation.I show why the threshold explanation fails and why the composite time tradeoff is indeed insensitive for worse-than-dead states.