Alosco Michael L, Spitznagel Mary Beth, Sweet Lawrence H, Josephson Richard, Hughes Joel, Gunstad John
Department of Psychology, Kent State University, Kent, Ohio, USA.
Geriatr Gerontol Int. 2015 Feb;15(2):174-81. doi: 10.1111/ggi.12245. Epub 2014 Feb 18.
Heart failure (HF) patients require assistance with activities of daily living (ADL). Poor physical fitness has recently been identified as a contributor to the high rates of disability in HF, though the mechanisms for such effects are unclear. Although not previously examined, decreased fitness might adversely impact ADL in HF through its known association with cognitive impairment, a key correlate of self-care abilities in this population. We sought to test this possibility using a model-based approach.
A total of 197 patients with HF completed a physical fitness test and a neuropsychological test battery. A total ADL composite was derived from the Lawton Brody scale. Structural equation modeling tested whether cognitive function mediated the association between physical fitness and total ADL.
Fitness was reduced, and cognitive dysfunction and impaired ADL were prevalent. The initially significant association between fitness and total ADL was attenuated when cognitive function was introduced as a mediator. This model showed good fit (comparative fit index=0.91: root mean-square error of approximations=0.077) with a significant indirect pathway between physical fitness and total ADL through cognitive function: Decreased physical fitness was associated with cognitive dysfunction (β=0.35), which predicted greater assistance with ADL (β=0.22).
Poor physical fitness might lead to decreased functional independence in HF through its negative effects on cognitive function. Prospective studies are required to confirm our findings, identify other mechanisms by which poor fitness impacts ADL, and examine whether exercise interventions can improve cognition and help preserve ADL independence in HF.
心力衰竭（HF）患者在日常生活活动（ADL）方面需要帮助。最近，身体机能差被认为是导致HF患者高致残率的一个因素，但其作用机制尚不清楚。虽然之前未进行过研究，但身体机能下降可能通过其与认知障碍的已知关联对HF患者的ADL产生不利影响，而认知障碍是该人群自我护理能力的一个关键相关因素。我们试图使用基于模型的方法来检验这种可能性。
共有197例HF患者完成了体能测试和神经心理测试组套。总ADL综合评分源自Lawton Brody量表。结构方程模型检验了认知功能是否介导了体能与总ADL之间的关联。
体能下降，认知功能障碍和ADL受损普遍存在。当将认知功能作为中介因素引入时，体能与总ADL之间最初的显著关联减弱。该模型显示拟合良好（比较拟合指数=0.91：近似均方根误差=0.077），体能与总ADL之间通过认知功能存在显著的间接路径：体能下降与认知功能障碍相关（β=0.35），认知功能障碍预示着在ADL方面需要更多帮助（β=0.22）。
身体机能差可能通过对认知功能的负面影响导致HF患者功能独立性下降。需要进行前瞻性研究以证实我们的发现，确定身体机能差影响ADL的其他机制，并研究运动干预是否可以改善认知功能并有助于维持HF患者的ADL独立性。
