Mitnitski Arnold, Song Xiaowei, Skoog Ingmar, Broe G A, Cox Jafna L, Grunfeld Eva, Rockwood Kenneth
Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
J Am Geriatr Soc. 2005 Dec;53(12):2184-9. doi: 10.1111/j.1532-5415.2005.00506.x.
To investigate the relationship between accumulated health-related problems (deficits), which define a frailty index in older adults, and mortality in population-based and clinical/institutional-based samples.
Cross-sectional and cohort studies.
Seven population-based and four clinical/institutional surveys in four developed countries.
Thirty-six thousand four hundred twenty-four people (58.5% women) aged 65 and older.
A frailty index was constructed as a proportion of all potential deficits (symptoms, signs, laboratory abnormalities, disabilities) expressed in a given individual. Relative frailty is defined as a proportion of deficits greater than average for age. Measures of deficits differed across the countries but included common elements.
In each country, community-dwelling elderly people accumulated deficits at about 3% per year. By contrast, people from clinical/institutional samples showed no relationship between frailty and age. Relative fitness/frailty in both sexes was highly correlated (correlation coefficient >0.95, P<.001) with mortality, although women, at any given age, were frailer and had lower mortality. On average, each unit increase in deficits increased by 4% the hazard rate for mortality (95% confidence interval=0.02-0.06).
Relative fitness and frailty can be defined in relation to deficit accumulation. In population studies from developed countries, deficit accumulation is robustly associated with mortality and with age. In samples (e.g., clinical/institutional) in which most people are frail, there is no relationship with age, suggesting that there are maximal values of deficit accumulation beyond which survival is unlikely.
研究老年人群中与健康相关的累积问题（缺陷）（其定义了一个衰弱指数）与基于人群样本以及基于临床/机构样本的死亡率之间的关系。
横断面研究和队列研究。
四个发达国家的七项基于人群的调查和四项临床/机构调查。
36424名65岁及以上的人群（女性占58.5%）。
衰弱指数构建为给定个体中所有潜在缺陷（症状、体征、实验室异常、残疾）的比例。相对衰弱定义为缺陷比例高于同龄人平均水平。各国的缺陷测量方法有所不同，但包含共同要素。
在每个国家，社区居住的老年人每年累积缺陷的比例约为3%。相比之下，临床/机构样本中的人群衰弱与年龄之间无关联。两性的相对健康/衰弱程度与死亡率高度相关（相关系数>0.95，P<0.001），尽管在任何给定年龄，女性更衰弱但死亡率更低。平均而言，缺陷每增加一个单位，死亡风险率增加4%（95%置信区间=0.02 - 0.06）。
相对健康和衰弱可根据缺陷累积来定义。在发达国家的人群研究中，缺陷累积与死亡率和年龄密切相关。在大多数人都衰弱的样本（如临床/机构样本）中，与年龄无关联，这表明存在缺陷累积的最大值，超过此值生存的可能性不大。
