Comparison of 2 frailty indexes for prediction of falls, disability, fractures, and death in older women.
BACKGROUND
Frailty, as defined by the index derived from the Cardiovascular Health Study (CHS index), predicts risk of adverse outcomes in older adults. Use of this index, however, is impractical in clinical practice.


METHODS
We conducted a prospective cohort study in 6701 women 69 years or older to compare the predictive validity of a simple frailty index with the components of weight loss, inability to rise from a chair 5 times without using arms, and reduced energy level (Study of Osteoporotic Fractures [SOF index]) with that of the CHS index with the components of unintentional weight loss, poor grip strength, reduced energy level, slow walking speed, and low level of physical activity. Women were classified as robust, of intermediate status, or frail using each index. Falls were reported every 4 months for 1 year. Disability (> or =1 new impairment in performing instrumental activities of daily living) was ascertained at 4(1/2) years, and fractures and deaths were ascertained during 9 years of follow-up. Area under the curve (AUC) statistics from receiver operating characteristic curve analysis and -2 log likelihood statistics were compared for models containing the CHS index vs the SOF index.


RESULTS
Increasing evidence of frailty as defined by either the CHS index or the SOF index was similarly associated with an increased risk of adverse outcomes. Frail women had a higher age-adjusted risk of recurrent falls (odds ratio, 2.4), disability (odds ratio, 2.2-2.8), nonspine fracture (hazard ratio, 1.4-1.5), hip fracture (hazard ratio, 1.7-1.8), and death (hazard ratio, 2.4-2.7) (P < .001 for all models). The AUC comparisons revealed no differences between models with the CHS index vs the SOF index in discriminating falls (AUC = 0.61 for both models; P = .66), disability (AUC = 0.64; P = .23), nonspine fracture (AUC = 0.55; P = .80), hip fracture (AUC = 0.63; P = .64), or death (AUC = 0.72; P = .10). Results were similar when -2 log likelihood statistics were compared.


CONCLUSIONS
The simple SOF index predicts risk of falls, disability, fracture, and death as well as the more complex CHS index and may provide a useful definition of frailty to identify older women at risk of adverse health outcomes in clinical practice.
Ensrud
Kristine E
KE
Center for Chronic Disease Outcomes Research, Veterans Affairs Medical Center, General Internal Medicine, Minneapolis, MN 55417, USA. ensru001@umn.edu
Ewing
Susan K
SK
Taylor
Brent C
BC
Fink
Howard A
HA
Cawthon
Peggy M
PM
Stone
Katie L
KL
Hillier
Teresa A
TA
Cauley
Jane A
JA
Hochberg
Marc C
MC
Rodondi
Nicolas
N
Tracy
J Kathleen
JK
Cummings
Steven R
SR
D000058:Accidental Falls / Q000706:statistics & numerical data*; D000368:Aged; D002423:Cause of Death; D006233:Persons with Disabilities; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology*; D016330:Frail Elderly; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D011237:Predictive Value of Tests; D011446:Prospective Studies