Frailty: Emergence and Consequences in Women Aged 65 and Older in the Women's Health Initiative Observational Study

Objectives: To define frailty using simple indicators; to identify risk factors for frailty as targets for prevention; and to investigate the predictive validity of this frailty classification for death, hospitalization, hip fracture, and activity of daily living (ADL) disability.

Design: Prospective study, the Women's Health Initiative Observational Study.

Setting: Forty U.S. clinical centers.

Participants: Forty thousand six hundred fifty-seven women aged 65 to 79 at baseline.

Measurements: Components of frailty included self-reported muscle weakness/impaired walking, exhaustion, low physical activity, and unintended weight loss between baseline and 3 years of follow-up. Death, hip fractures, ADL disability, and hospitalizations were ascertained during an average of 5.9 years of follow-up.

Results: Baseline frailty was classified in 16.3% of participants, and incident frailty at 3-years was 14.8%. Older age, chronic conditions, smoking, and depressive symptom score were positively associated with incident frailty, whereas income, moderate alcohol use, living alone, and self-reported health were inversely associated. Being underweight, overweight, or obese all carried significantly higher risk of frailty than normal weight. Baseline frailty independently predicted risk of death (hazard ratio (HR)=1.71, 95% confidence interval (CI)=1.48-1.97), hip fracture (HR=1.57, 95% CI=1.11-2.20), ADL disability (odds ratio (OR)=3.15, 95% CI=2.47-4.02), and hospitalizations (OR=1.95, 95% CI=1.72-2.22) after adjustment for demographic characteristics, health behaviors, disability, and comorbid conditions.

Conclusion: These results support the robustness of the concept of frailty as a geriatric syndrome that predicts several poor outcomes in older women. Underweight, obesity, smoking, and depressive symptoms are strongly associated with the development of frailty and represent important targets for prevention.