School of Health and Related Research, University of Sheffield, Sheffield, UK.
Pharmacoeconomics. 2012 Jan;30(1):47-61. doi: 10.2165/11539910-000000000-00000.
An important methodological issue in economic evaluations of healthcare is how to include productivity costs (the costs related to reduced productivity due to illness, disability and premature death). Traditionally, they were included in the numerator of a cost-effectiveness analysis, through either the human-capital or the friction-cost method. It has been argued, however, that productivity costs are already included in the denominator (i.e. in the QALY measure) because respondents consider the effect a given health state will have on their income when valuing health states. If that is the case, many previous economic evaluations might have double counted productivity costs by including them in both the numerator and the denominator.
The aim of this study was to determine whether respondents valuing EQ-5D health states using the time trade-off (TTO) method spontaneously consider income effects, whether this consideration influences subsequent valuations and whether explicit ex post instructions influence valuations.
Through an online survey, we asked 321 members of the Dutch general population to value four EQ-5D health states through three different TTO exercises. The first exercise was a standard TTO question. Respondents were then asked whether they had included income effects. Depending on their answer, the second TTO exercise instructed them to either include or exclude income effects. The third TTO exercise provided explicit information regarding the income loss associated with the health state.
Data were available from 321 members of the Dutch general public. Of these respondents, 49% stated they had spontaneously included income effects. Twenty-five percent of the sample did not trade any time in any of the TTO exercises and these respondents were excluded from the analysis. Results of t-tests showed there were only weakly significant differences in valuations for one health state between those who spontaneously included income effects and those who did not. Explicit instruction led to some significant differences at the aggregate level, but the effect was inconsistent at the individual level. When explicit information on the amount of income loss was provided, all states were valued lower when associated with a larger income loss.
This study offers further evidence indicating that income losses do not significantly affect health state valuations.
在医疗保健的经济评估中，一个重要的方法学问题是如何纳入生产力成本（因疾病、残疾和过早死亡导致生产力下降而产生的成本）。传统上，它们通过人力资本法或摩擦成本法被纳入成本效益分析的分子中。然而，有人认为，生产力成本已经包含在分母中（即在 QALY 衡量标准中），因为受访者在评估健康状况时会考虑给定健康状况对其收入的影响。如果是这样，许多先前的经济评估可能已经通过同时将生产力成本纳入分子和分母而重复计算了生产力成本。
本研究旨在确定使用时间权衡（TTO）方法评估 EQ-5D 健康状况的受访者是否会自发考虑收入效应，这种考虑是否会影响后续的评估，以及明确的事后指导是否会影响评估。
通过在线调查，我们要求 321 名荷兰普通民众使用三种不同的 TTO 练习来评估四个 EQ-5D 健康状况。第一个练习是一个标准的 TTO 问题。然后，受访者被问及他们是否考虑了收入效应。根据他们的回答，第二个 TTO 练习指示他们包括或不包括收入效应。第三个 TTO 练习提供了与健康状况相关的收入损失的明确信息。
从 321 名荷兰普通公众中获得了数据。在这些受访者中，49%表示他们自发地包括了收入效应。有 25%的样本在任何 TTO 练习中都没有进行任何时间交易，这些受访者被排除在分析之外。t 检验的结果显示，在那些自发考虑收入效应的人和那些不考虑的人之间，只有一个健康状况的评估存在微弱的显著差异。在总体水平上，明确的指导导致了一些显著的差异，但在个体水平上则不一致。当提供有关收入损失金额的明确信息时，当与更大的收入损失相关联时，所有状态的估值都较低。
本研究提供了进一步的证据，表明收入损失不会显著影响健康状况的估值。
