Is functional mobility an independent mortality risk factor in subjects with dementia?

Objective: To investigate whether functional mobility is a predictor of 12-month mortality in elderly subjects with dementia.

Study design: Prospective multicentre study performed in nine French university hospitals. Patients aged 75 years or more and hospitalised in medical wards via the emergency department were eligible. Those with a diagnosis of dementia were considered in the analyses.

Main outcome measures: Patients' characteristics obtained through comprehensive geriatric assessment performed during the first week of hospitalisation. Functional mobility was assessed using the timed "Up & Go" test. The main outcome was time to death within the 12 months of follow-up. Bivariable relationships between each risk factor and mortality were assessed using a Cox regression model with one explanatory variable. For multivariable analysis, the Cox regression model was used in a stepwise method after examining potential confounders and interactions.

Results: In all, 589 patients had a diagnosis of dementia, and were considered in the present analyses. Their mean age was 86±6years and most (69%) were female. The prevalence of functional mobility disorders was 86%. After 12 months, 232 (39%) had died. After adjustment for potential confounders, functional mobility was associated with a significantly higher risk of 12-month mortality (HR=1.66; 95% CI=1.02-2.71; p=0.04).

Conclusions: Impaired functional mobility as assessed by the timed Up & Go test identifies subjects with dementia at risk of unfavourable outcome.