Further evidence for the importance of subclinical functional limitation and subclinical disability assessment in gerontology and geriatrics.

OBJECTIVE: The objectives of this work were to determine the prevalence of self-reported subclinical status for functional limitation and disability at baseline and assess their independent effects on the onset of functional limitation and disability 1-2 years later.
METHODS: Nine hundred ninety-eight African American men and women 49-65 years old in St. Louis, MO, received comprehensive in-home evaluations at baseline and two annual telephone follow-ups. Outcome measures included walking a half-mile, climbing steps, stooping-crouching-kneeling, lifting or carrying 10 lbs., and doing heavy housework. RESULT: The baseline prevalence of subclinical status was 26.4% for walking a half-mile, 26.8% for climbing steps, 39.0% for stooping-crouching-kneeling, 29.1% for lifting or carrying 10 lbs., and 22.7% for doing heavy housework. The adjusted odds ratios for the task-specific subclinical status measure at baseline on developing difficulty 1-2 years later were 1.68 (p < .05) for walking a half-mile, 4.46 (p < .001) for climbing steps, 2.48 (p < .001) for stooping-crouching-kneeling, 2.51 (p < .001) for lifting or carrying 10 lbs., and 2.22 (p < .001) for doing heavy housework. Performance tests (tandem stand, chair stands, and preferred gait speed) did not have consistent independent effects on the onset of functional limitation or disability.
CONCLUSION: The subclinical status measures were the main predictors of the onset of difficulty in all tasks and functions 1-2 years later. Interventions to reduce frailty should focus on self-reported subclinical status as an early warning system.