Longitudinal Study of Transitions in Disability and Death among Older Persons

描述（由申请人提供）：本提案的总体目标是制定适当的方法来描述与年龄相关的日常生活活动（adl）变化，同时考虑老年人之间的差异生存模式。耶鲁突发事件项目（PEP）是一项正在进行的ADL残疾的纵向研究，它跟踪了一大批社区生活的老年人超过十年。进行了每月访谈和每隔18个月进行一次综合评估，以评估ADL残疾、可能的风险因素、潜在的干预事件和死亡。PEP已经记录了相关信息，这些信息有助于阐明ADL残疾发生和恢复的机制，并提供了强有力的证据，证明残疾是一个具有相当异质性和多种潜在途径的可逆和复发事件。然而，残疾程度越重的受试者往往死得越早，因此，利用现有的随访观察对残疾程度和总体负担的估计可能存在偏差，因为ADL数据的数量会根据受试者的生存时间而变化。在目前的纵向研究分析方法中，死亡通常以与非衰老研究中的辍学相似的方式处理，或被视为独立审查，并且通常在死亡时间接近的情况下进行回顾性分析。大多数辍学模型假设辍学后存在潜在的反应，这不适用于老年人与年龄相关的功能变化，因为死亡是截断测量的主要原因。因此，在纵向老龄化研究或任何死亡是不可避免事件的研究中，需要采用不同的分析策略来处理死亡。我们的第一个目标是描述ADL的序数反应，我们认为这是与死亡风险过程相关的潜在失能过程的表现轨迹。我们的第二个目标是发现代表致残过程和死亡之间复杂关系的独特模式。我们的第三个目标是研究ADL状态（即ADL残疾的（再）发生、恶化、改善和恢复）和死亡之间的动态转变。在所有目标中，将调查诸如年龄、性别、认知障碍、身体活动水平、抑郁、急性或慢性合并症（例如中风、听力和感觉障碍）的存在以及身体虚弱等风险因素的作用。我们的研究结果将为老龄化研究人员提供与衰老相关的ADL轨迹的信息，这些轨迹具有不同的生存模式。使用每月评估的PEP数据解决了先前的担忧，即缺乏覆盖死亡前一段时间以上的频繁测量限制了我们对死亡风险的理解，并使关于ADL轨迹的研究结果产生偏差。本文提出的方法一般适用于其他纵向研究，其中死亡是一个竞争事件，如阿尔茨海默病退伍军人认知功能的纵向研究，艾滋病患者免疫功能的研究和治疗后癌症患者生活质量的研究。公共卫生相关性：老年人在日常生活活动方面的残疾导致个人和长期护理费用高昂，往往导致不利的健康结果。因此，调查与老年人ADL的发生、恶化、改善和恢复以及死亡有关的模式和因素是一项重要的临床和科学任务。

DESCRIPTION (provided by applicant): The overall objective of this proposal is to develop proper methods for characterizing aging-related changes in activities of daily living (ADLs) while accounting for differential survival patterns among older persons. The Yale Precipitating Events Project (PEP) is an ongoing longitudinal study of ADL disability, which has followed a large cohort of community-living older persons for over ten years. Monthly interviews and comprehensive assessments at eighteen-month intervals have been conducted to assess ADL disability, possible risk factors, potential intervening events, and deaths. PEP has documented relevant information that helps to elucidate the mechanisms underlying the occurrence and recovery of ADL disability and provided strong evidence that disability is a reversible and recurrent event with considerable heterogeneity and multiple potential pathways. However participants with greater disability tend to die earlier, hence the estimation of the extent of and overall burden of disability using available follow-up observations may be biased because the amount of ADL data varies according to participants' survival times. In current analytic methods for longitudinal study, death is typically dealt with in a similar fashion as dropout in non-aging research or treated as independent censoring, and often retrospective analysis is conducted conditioning on the proximity of death time. Most dropout models assume the existence of potential response after dropout, which does not apply to the aging-related functional change in older persons when death is the main reason for truncated measurements. Thus, a different analytic strategy is needed to deal with death in longitudinal aging research or any research in which death is an inevitable event. Our first aim is to depict the ADL ordinal response, which we view as manifested trajectory of underlying disabling process that is related to the risk process of death. Our second aim is to discover the distinct patterns representing the complex relationship between the disabling process and death. Our third aim is to study the dynamic transitions among the ADL states (i.e., (re)occurrence, worsening, improvement, and recovery of ADL disability) and death. In all the aims, the role of risk factors such as age, gender, cognitive impairment, physical activity level, depression, existence of acute or chronic comorbid conditions (e.g., stroke, hearing and sensory impairment) and physical frailty will be investigated. The findings from our proposal will provide aging researchers with an informative picture of aging-related ADL trajectories with varying survival patterns. The use of PEP data with monthly assessments addresses the previous concern that lack of frequent measurements that cover more than the period immediately before death has limited our understanding of the risk of death and biased the findings on ADL trajectories. The methods developed in this proposal are generally applicable to other longitudinal studies where death is a competing event, such as the longitudinal study of cognitive function in Veterans with Alzheimer's disease, study of the immune function in AIDS patients and study of quality of life in post-treatment cancer patients. PUBLIC HEALTH RELEVANCE: Disability in activities of daily living (ADL) in older persons incurs high cost in personal and long-term cares often leads to adverse health outcomes. Investigating patterns and factors associated with occurrence, deterioration, improvement and recovery of ADL and with death in older persons thus constitutes an important clinical and scientific task.