Prediction of disability-free survival in healthy older people

Abstract

Prolonging survival in good health is a fundamental societal goal. However, the leading determinants of disability-free survival in healthy older people have not been well established. Data from ASPREE, a bi-national placebo-controlled trial of aspirin with 4.7 years median follow-up, was analysed. At enrolment, participants were healthy and without prior cardiovascular events, dementia or persistent physical disability. Disability-free survival outcome was defined as absence of dementia, persistent disability or death. Selection of potential predictors from amongst 25 biomedical, psychosocial and lifestyle variables including recognized geriatric risk factors, utilizing a machine-learning approach. Separate models were developed for men and women. The selected predictors were evaluated in a multivariable Cox proportional hazards model and validated internally by bootstrapping. We included 19,114 Australian and US participants aged ≥65 years (median 74 years, IQR 71.6–77.7). Common predictors of a worse prognosis in both sexes included higher age, lower Modified Mini-Mental State Examination score, lower gait speed, lower grip strength and abnormal (low or elevated) body mass index. Additional risk factors for men included current smoking, and abnormal eGFR. In women, diabetes and depression were additional predictors. The biased-corrected areas under the receiver operating characteristic curves for the final prognostic models at 5 years were 0.72 for men and 0.75 for women. Final models showed good calibration between the observed and predicted risks. We developed a prediction model in which age, cognitive function and gait speed were the strongest predictors of disability-free survival in healthy older people.Trial registrationClinicaltrials.gov (NCT01038583)

Predicting Disability Using a Nomogram of the Tilburg Frailty Indicator (TFI)

“…Another systematic review also found an association between walking speed and the probability of disability [ 32 ]. A recently developed prediction model demonstrated that age, walking speed, and cognitive function were the strongest predictors of disability-free survival in healthy older people [ 33 ]. We only found two studies, both longitudinal, carried out in the Netherlands aimed at predicting disability assessed with the GARS by frailty items [ 34 , 35 ].…”

Effects of physical activity participation on cognitive impairment in older adults population with disabilities

“…Furthermore, older adults individuals who achieved the recommended MVPA level of 150 min per week exhibited superior cognitive function relative to those who failed to meet this standard; the latter group was 1.63 times more likely to experience cognitive decline ( 10 ). Furthermore, in both genders of the older adults, higher age, lower cognitive function, lower gait speed, and lower grip strength were predictors of difficulty living with disability ( 11 ). Over a 10-year follow-up of 1,096 participants with a mean age of 69.4 ± 5.8 years, the group with the lowest grip strength had a significantly greater decline in cognitive function compared to the group with the highest grip strength (estimate = 0.06, p = 0.039), indicating that low grip strength can predict 10 years of cognitive decline ( 12 ).…”

Occupational characteristics and disability-free survival after retirement age: an exploratory analysis from the ASPREE study

“…However, with many societies experiencing rapid aging of their populations, another social and economic imperative is to maintain an individual’s independence as long as possible, thereby reducing the need for institutional care. Disability-free survival, defined as survival free of severe physical disability or dementia has been proposed as a surrogate measure of independence, of particular relevance to studies of older people ( 10 ). To date, there is little information available about the impact of occupational factors on this important measure of population health.…”