Figure 1.

(A) Hypothetical trajectories of functional status for patients experiencing recurrent acute exacerbations of chronic lung disease who are frail (red line) and not frail (blue line). Frail patients are susceptible to more frequent exacerbations with less recovery in between, resulting in faster loss of functional status, earlier onset of disability, and a shorter lifespan. (B) Hypothetical trajectories for patients who are frail (red line) or not frail (blue line) prior to becoming critically ill. The thickness of the trajectory lines represents the proportion of patients in each trajectory. For a given insult, frail patients are susceptible to becoming critically ill sooner. Patients who are frail prior to critical illness are more likely to die in the hospital and more likely to develop chronic critical illness or severe disability leading to an early death. If they survive their critical illness, they are prone to recover functional status more slowly or develop permanent disability and a shorter lifespan than those who are not frail.