Depressive symptoms and impaired physical function after acute lung injury: a 2-year longitudinal study

Abstract

Rationale: Survivors of acute lung injury (ALI) frequently have substantial depressive symptoms and physical impairment, but the longitudinal epidemiology of these conditions remains unclear.

Objectives: To evaluate the 2-year incidence and duration of depressive symptoms and physical impairment after ALI, as well as risk factors for these conditions.

Methods: This prospective, longitudinal cohort study recruited patients from 13 intensive care units (ICUs) in four hospitals, with follow-up 3, 6, 12, and 24 months after ALI. The outcomes were Hospital Anxiety and Depression Scale depression score greater than or equal to 8 ("depressive symptoms") in patients without a history of depression before ALI, and two or more dependencies in instrumental activities of daily living ("impaired physical function") in patients without baseline impairment.

Measurements and main results: During 2-year follow-up of 186 ALI survivors, the cumulative incidences of depressive symptoms and impaired physical function were 40 and 66%, respectively, with greatest incidence by 3-month follow-up; modal durations were greater than 21 months for each outcome. Risk factors for incident depressive symptoms were education 12 years or less, baseline disability or unemployment, higher baseline medical comorbidity, and lower blood glucose in the ICU. Risk factors for incident impaired physical function were longer ICU stay and prior depressive symptoms.

Conclusions: Incident depressive symptoms and impaired physical function are common and long-lasting during the first 2 years after ALI. Interventions targeting potentially modifiable risk factors (e.g., substantial depressive symptoms in early recovery) should be evaluated to improve ALI survivors' long-term outcomes.

Figure 1.

Flow diagram of study participants. ^aSome patients had a follow-up visit but did not have complete Hospital Anxiety and Depression Scale depression score (HADd) or number of dependencies in instrumental activities of daily living (IADL) data for the following reasons, respectively (cognitively incapable/physically incapable/other): At 3 months, 22 did not have complete HADd data (9/5/8), and 13 did not have complete IADL data (4/4/5). At 6 months, 13 did not have complete HADd data (5/2/6), and 5 did not have complete IADL data (0/2/3). At 12 months, 14 did not have complete HADd data (5/4/5), and 4 did not have complete IADL data (1/3/0). At 24 months, 10 did not have complete HADd data (0/6/4), and 4 did not did not have complete IADL data (0/2/2). The proportions with HADd ≥ 8 or IADL ≥ 2 reflect point prevalences, not incidences. Cross-sectionally, depressive symptoms and impaired physical function were related, *P < 0.05 or **P < 0.001.

Figure 2.

Cumulative incidence of depressive symptoms or impaired physical function in the first 2 years after acute lung injury. During 2-year follow-up after acute lung injury, the cumulative incidence of depressive symptoms was 40%, and the cumulative incidence of impaired physical function was 66%. Incidence was highest by the 3-month follow-up and declined thereafter.

Figure 3.

Recovery from incident depressive symptoms or impaired physical function in the first 2 years after acute lung injury. Thin lines and thick lines indicate individual and mean trajectories, respectively, for patients whose conditions remitted (A and C) and did not remit (B and D) during 2-year follow-up after acute lung injury. Horizontal dashed lines indicate thresholds for depressive symptoms (A and B) and impaired physical function (C and D). HAD = Hospital Anxiety and Depression Scale; IADL = instrumental activities of daily living.