Collaborative Research: Adding Extrinsic Goals to the QALY Model (with Gordon Hazen)

评估健康质量的方法是医疗成本效益分析的核心。最重要的这种方法是质量调整寿命年(或QALY)，在该年中，患者的寿命与健康质量成比例地被赋予权重。然而，许多研究表明，测量的QALY与患者目前的健康状况之间的相关性充其量是适度的。此外，众所周知，当人的余生很长时，可以用生命来换取更好的健康质量，但当生命很短时就不会；健康质量较差的人可能宁愿只活到重要的人生里程碑实现而不是更长。目前的QALY模型不能适应这些现象。为了解决这些担忧，研究人员将研究将生活目标纳入健康偏好模型的方法。QALY模型已经解决了与寿命成正比的“持续目标”，例如最大限度地减少慢性疼痛或保持身体活动能力。其他被称为“外在目标”的目标，比如完成一个重要的项目或看到一个孩子从大学毕业，在本质上是不同的；他们的成就的影响与寿命无关。QALY没有解决这些问题。研究人员将QALY模型推广为既包含持续目标又包含外部目标。在这一模型的指导下，研究人员将进行实证研究，以确定对普通公众和医疗患者重要的外在目标的种类。他们将进行理论研究，调查外部目标的潜在偏好模型，包括多个外部目标的方法，以及当添加外部目标时对已发表的医疗决策分析的影响。他们将确定外在目标是否有助于解释QALY模型所禁止的看似合理的行为，或者是否能比QALY更好地将衡量的偏好与当前的健康状况相关联。尽管有其局限性，QALY模型已经成为在医疗成本效果分析中模拟患者偏好的标准。研究人员的外在目标模型构成了对这一标准的基本和原创性的扩充。它有可能使社会受益，因为它大大拓宽了这些分析中包括的患者和社区偏好的类型。

Methods for evaluating health quality are central to medical cost-effectiveness analyses. The most important such method is the quality-adjusted life year (or QALY), in which a patient's length of life is given weight proportional to quality of health. However, numerous studies have demonstrated that the correlation between measured QALYs and a patient's current health is at best modest. Moreover, it is known that individuals may trade lifetime for improved health quality when remaining lifetime is long, but not when it is short; and that those with poor health quality may prefer to survive only until important life milestones are achieved and no longer. Current QALY models do not accomodate these sorts of phenomena.To address these concerns, the investigators will examine methods for incorporating life goals into health preference models. The QALY model already addresses "ongoing goals" that have impact proportional to length of life, such as minimizing chronic pain or maintaining physical mobility. Other goals, termed "extrinsic goals," such as completing an important project or seeing a child graduate from college, are qualitatively different; their achievement has impact independent of length of life. These are not addressed by QALYs. The investigators have generalized the QALY model to incorporate both ongoing goals and extrinsic goals. Guided by this model, the investigators will conduct empirical studies to characterize the kinds of extrinsic goals that are important for the general public and medical patients. They will conduct theoretical studies investigating potential preference models for extrinsic goals, methods for including multiple extrinsic goals, and impacts on published medical decision analyses when extrinsic goals are added. They will determine if extrinsic goals can help explain plausible behavior forbidden by the QALY model or yield better correlation of measured preferences with current health than does QALY. Despite its limitations, the QALY model has become the standard for modeling patient preferences in medical cost-effectiveness analyses. The investigators' extrinsic-goal model constitutes a fundamental and original augmentation of this standard. It has the potential to benefit society by substantially broadening the types of patient and community preferences included in these analyses.