Persistent mobility deficit in the absence of deficits in activities of daily living: a risk factor for mortality.

OBJECTIVES

To investigate the extent to which self-reported mobility deficit in the absence of impairment in activities of daily living (ADL) is associated with elevated mortality risk.

DESIGN

Prospective cohort study, with annual assessments of mobility and ADL status and ongoing monitoring of vital status.

SETTING

Population-based cohort drawn from Medicare enrollees in New York City.

PARTICIPANTS

One thousand two hundred ninety-eight older adults reporting functional status at baseline (1992-1994) and 2 years later.

MEASUREMENTS

Subjects reported mobility (e.g., walking, climbing stairs, and rising from a chair) and ADL (e.g., bathing, toilet use, dressing, grooming, and feeding) limitations. Two-year functional status trajectories were noted. We used two additional follow-up periods, at 2 and 4 years, to examine the likelihood that older people with mobility deficit may face an increased risk of death without first passing through a state of enduring ADL disability.

RESULTS

At 2 years, 12.7% had incident mobility deficit without ADL disability, and 21.3% were persistently disabled in mobility without ADL disability. Relative to subjects free of disability at baseline and follow-up, risk of mortality in the incident mobility deficit group was elevated at 2 and 4 years but did not achieve statistical significance. By contrast, for subjects with persistent mobility impairment who did not report ADL impairment, the mortality risk was significantly elevated both at 2 years (relative risk (RR) = 2.5; 95% confidence interval (CI) = 1.1-5.7)) and 4 years (RR = 2.9; 95% CI = 1.7-4.9)) of follow-up. Mortality was significantly elevated in this group in analyses restricted to respondents with no or only one comorbid condition.

CONCLUSION

Continuing, self-reported mobility impairment in the absence of ADL deficit is a risk factor for mortality. Older people with self-reported mobility deficit face an increased risk of mortality without first passing through enduring states of ADL disability.