Identifying mobility heterogeneity in very frail older adults. Are frail people all the same?

Frail older adults sustain mobility limitations; however, clinical experience suggests that their mobility characteristics are far from being homogeneous. We conducted a prospective analysis to identify mobility heterogeneity in 1160 very frail older adults and we investigated the associations between mobility limitation profiles and further institutionalization and death. A cluster analysis using 11 self-reported mobility indicators was used to identify mobility profiles (MPs). At baseline, MPs varies from having mild limitations (n=370), moderate limitations (n=470), to severe limitations (n=320). Mild MP did not have mobility disability. Moderate MP had upper limb task limitations and mild lower limb task difficulties. Severe MP portrayed more deficits in lower limbs tasks functions with important mobility disability. After 2 years of follow up, the Severe MP group had a higher risk of mortality and nursing home placement when compared with Mild MP. Higher incidences of hip fracture and hospitalization were associated with the severity of MP. Even among very frail elderly, we identified different levels of mobility, cautioning against to treat them as a homogeneous group. Mobility heterogeneity predicted mortality and nursing home placement in a dose response manner. None of the mobility indicators individually predicted the outcomes as strongly as the profiles. Identification of this mobility heterogeneity may assist on planning of health programs in very frail elderly.