Disability among elderly survivors of mechanical ventilation

Studies of long-term functional outcomes of elderly survivors of mechanical ventilation (MV) are limited to local samples and biased retrospective, proxy-reported preadmission functional status.

To assess the impact on disability of hospitalization with MV, compared with hospitalization without MV, accounting for prospectively assessed prior functional status.

Retrospective population-based longitudinal cohort study of Medicare beneficiaries age 65 and older enrolled in the Medicare Current Beneficiary Survey, 1996-2003.

Premeasures and postmeasures of disability included mobility difficulty and weighted activities of daily living disability scores ranging from 0 (not disabled) to 100 (completely disabled) based on self-reported health and functional status collected 1 year apart. Among 54,771 person-years (PY) of observation over 7 calendar years of data, 42,890 PY involved no hospitalization, 11,347 PY involved a hospitalization without MV, and 534 PY included a hospitalization with MV. Mortality at 1 year was 8.9%, 23.9%, and 72.5%, respectively. The level of disability at the postassessment was substantially higher for a prototypical patient who survived after hospitalization with MV (adjusted activities of daily living disability score [95% confidence interval] 14.9 [12.2-17.7]; adjusted mobility difficulty score [95% confidence interval] 25.4 [22.4-28.4]) compared with an otherwise identical patient who survived hospitalization without MV (11.5 [11.1-11.9] and 22.3 [21.8-22.9]) or who was not hospitalized (8.0 [7.9-8.1] and 13.4 [13.3-13.6]).

The greater marginal increase in disability among survivors of MV compared with survivors of hospitalization without MV is larger than would be predicted from prior functional status.