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

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

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.

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.

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).

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