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

评价卫生质量的方法是医疗成本效益分析的核心。这类方法中最重要的是质量调整生命年（QALY），在这种方法中，病人的生命长度被赋予与健康质量成比例的权重。然而，大量研究表明，测量的质量aly与患者当前健康状况之间的相关性充其量是适度的。此外，众所周知，在剩余寿命较长的情况下，个人可以用一生来换取改善健康质量，但在剩余寿命较短的情况下则不然；那些健康状况不佳的人可能宁愿只活到人生的重要里程碑，而不再活下去。目前的QALY模型不能适应这些现象。为了解决这些问题，研究人员将研究将生活目标纳入健康偏好模型的方法。QALY模型已经解决了与生命长度成正比的“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。其他目标，被称为“外在目标”，如完成一个重要项目或看到孩子从大学毕业，在质量上是不同的；他们的成就的影响与寿命长短无关。QALYs不解决这些问题。研究者已经将QALY模型一般化，以纳入持续目标和外在目标。在此模型的指导下，研究者将进行实证研究，以表征对公众和医疗患者重要的各种外在目标。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被QALY模型禁止的貌似合理的行为，或者比QALY模型更好地将测量的偏好与当前健康状况联系起来。尽管有其局限性，QALY模型已成为在医疗成本效益分析中建模患者偏好的标准。研究者的外部目标模型构成了对这一标准的根本性和原创性的扩充。它有可能通过大大扩大这些分析中包括的患者和社区偏好的类型来造福社会。

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.