Development and validation of a functional morbidity index to predict mortality in community-dwelling elders.
OBJECTIVE
Functional measures have a great appeal for prognostic instruments because they are associated with mortality, they represent the end-impact of disease on the patient, and information about them can be obtained directly from the patient. However, there are no prognostic indices that have been developed for community-dwelling elders based primarily on functional measures. Our objective in this study was to develop and validate a prognostic index for 2-year mortality in community-dwelling elders, based on self-reported functional status, age, and gender.


METHODS
Population-based cohort study from 1993 to 1995.


METHODS
Community-dwelling elders within the United States.


METHODS
Subjects, age > or =70 (N = 7,393), from the Asset and Health Dynamics Among the Oldest Old study. We developed the index in 4,516 participants (mean age 78, 84% white, 61% female), and validated it in 2,877 different participants (mean age 78, 73% white, 61% female).


METHODS
Prediction of 2-year mortality using risk factors such as activities of daily living, instrumental activities of daily living, additional measures of physical function, age, and gender.


RESULTS
Overall mortality was 10% in the development cohort and 12% in the validation cohort. In the development cohort, 6 independent predictors of mortality were identified and weighted, using logistic regression models, to create a point scale: male gender, 2 points; age (76 to 80, 1 point; >80, 2 points); dependence in bathing, 1 point; dependence in shopping, 2 points; difficulty walking several blocks, 2 points; and difficulty pulling or pushing heavy objects, 1 point. We calculated risk scores for each patient by adding the points of each independent risk factor present. In the development cohort, 2-year mortality was 3% in the lowest risk group (0 to 2 points), 11% in the middle risk group (3 to 6 points), and 34% in the highest risk group (>7 points). In the validation cohort, 2-year mortality was 5% in the lowest risk group, 12% in the middle risk group, and 36% in the highest risk group. The c-statistics for the point system were 0.76 and 0.74 in the development and validation cohorts, respectively.


CONCLUSIONS
This prognostic index, which relies solely on self-reported functional status, age, and gender, provides a simple and accurate method of stratifying community-dwelling elders into groups at varying risk of mortality.
Carey
Elise C
EC
Division of Geriatrics, University of California San Francisco, San Francisco, California, USA. ecarson@medicine.ucsf.edu
Walter
Louise C
LC
Lindquist
Karla
K
Covinsky
Kenneth E
KE
D000203:Activities of Daily Living; D000367:Age Factors; D000368:Aged / Q000502:physiology*; D005260:Female; D015577:Geriatric Assessment; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D009026:Mortality; D011379:Prognosis; D015203:Reproducibility of Results; D012111:Residence Characteristics; D012737:Sex Factors