Volume 53, Issue 12 p. 2184-2189

Relative Fitness and Frailty of Elderly Men and Women in Developed Countries and Their Relationship with Mortality

Arnold Mitnitski PhD

Arnold Mitnitski PhD

From the Divisions of * Geriatric Medicine, Cardiology, and Medical Oncology, § Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada Institute of Clinical Neuroscience, University of Gothenburg, Gothenburg, Sweden Prince of Wales Medical Research Institute and University of New South Wales, Sydney, New South Wales, Australia

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Xiaowei Song PhD

Xiaowei Song PhD

From the Divisions of * Geriatric Medicine, Cardiology, and Medical Oncology, § Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada Institute of Clinical Neuroscience, University of Gothenburg, Gothenburg, Sweden Prince of Wales Medical Research Institute and University of New South Wales, Sydney, New South Wales, Australia

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Ingmar Skoog PhD, MD

Ingmar Skoog PhD, MD

From the Divisions of * Geriatric Medicine, Cardiology, and Medical Oncology, § Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada Institute of Clinical Neuroscience, University of Gothenburg, Gothenburg, Sweden Prince of Wales Medical Research Institute and University of New South Wales, Sydney, New South Wales, Australia

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GA Broe PhD

GA Broe PhD

From the Divisions of * Geriatric Medicine, Cardiology, and Medical Oncology, § Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada Institute of Clinical Neuroscience, University of Gothenburg, Gothenburg, Sweden Prince of Wales Medical Research Institute and University of New South Wales, Sydney, New South Wales, Australia

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Jafna L. Cox MD

Jafna L. Cox MD

From the Divisions of * Geriatric Medicine, Cardiology, and Medical Oncology, § Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada Institute of Clinical Neuroscience, University of Gothenburg, Gothenburg, Sweden Prince of Wales Medical Research Institute and University of New South Wales, Sydney, New South Wales, Australia

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Eva Grunfeld MD

Eva Grunfeld MD

From the Divisions of * Geriatric Medicine, Cardiology, and Medical Oncology, § Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada Institute of Clinical Neuroscience, University of Gothenburg, Gothenburg, Sweden Prince of Wales Medical Research Institute and University of New South Wales, Sydney, New South Wales, Australia

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Kenneth Rockwood MD

Kenneth Rockwood MD

From the Divisions of * Geriatric Medicine, Cardiology, and Medical Oncology, § Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada Institute of Clinical Neuroscience, University of Gothenburg, Gothenburg, Sweden Prince of Wales Medical Research Institute and University of New South Wales, Sydney, New South Wales, Australia

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First published: 18 October 2005
Citations: 419
Address correspondence to Kenneth Rockwood, MD, 1431–5955 Veterans Memorial Lane, Halifax NS, B3H 2E1, Canada. E-mail: [email protected]

Abstract

Objectives: 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.

Design: Cross-sectional and cohort studies.

Setting: Seven population-based and four clinical/institutional surveys in four developed countries.

Participants: Thirty-six thousand four hundred twenty-four people (58.5% women) aged 65 and older.

Measurements: 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.

Results: 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).

Conclusion: 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.