Longitudinal Study of Transitions in Disability and Death among Older Persons

描述(由申请人提供)：这项提案的总体目标是开发适当的方法来表征日常生活活动(ADL)中与老龄化有关的变化，同时考虑到老年人之间不同的生存模式。耶鲁大学沉淀事件项目(PEP)是一项正在进行的关于ADL残疾的纵向研究，跟踪调查了一大批居住在社区的老年人十多年。每隔18个月进行每月访谈和全面评估，以评估ADL残疾、可能的危险因素、潜在的干预事件和死亡。PEP记录了相关信息，有助于阐明ADL残疾发生和恢复的潜在机制，并提供了强有力的证据，表明残疾是一种可逆和反复发生的事件，具有相当大的异质性和多个潜在的途径。然而，残疾程度较高的参与者往往死亡得更早，因此，使用现有的后续观察对残疾程度和总体负担的估计可能是有偏见的，因为日常生活能力数据量因参与者的生存时间而异。在目前的纵向研究分析方法中，死亡通常被以类似于非老龄化研究中辍学的方式来处理，或者被视为独立的审查，并且通常以死亡时间的接近为条件进行回顾分析。大多数退学模型假定退学后存在潜在的反应，当死亡是截断测量的主要原因时，这不适用于老年人与衰老相关的功能变化。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，需要一种不同的分析策略来处理死亡。我们的第一个目标是描绘ADL顺序反应，我们认为这是与死亡风险过程相关的潜在残疾过程的显性轨迹。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不同模式。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)与死亡之间的动态转变。在所有目标中，将调查年龄、性别、认知障碍、体力活动水平、抑郁、是否存在急性或慢性并存情况(如中风、听力和感觉障碍)以及身体虚弱等风险因素的作用。我们建议的研究结果将为老年研究人员提供一幅与衰老相关的ADL轨迹的信息图，这些轨迹具有不同的生存模式。PEP数据与每月评估的使用解决了之前的担忧，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了解，并对ADL轨迹的研究结果产生了偏见。这项建议中开发的方法一般适用于死亡是竞争事件的其他纵向研究，例如阿尔茨海默病退伍军人认知功能的纵向研究，艾滋病患者的免疫功能研究，以及治疗后癌症患者的生活质量研究。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的高昂成本，往往导致不利的健康后果。因此，研究老年人日常生活能力的发生、恶化、改善和恢复以及与死亡相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.