Survivors of acute lung injury are likely to experience depression and physical impairment for up to 2 years after leaving the intensive care unit.

In a prospective study, 40% of patients had new-onset depression and 66% had new physical impairment after discharge. The findings seem inextricably linked on both psychological and physiological levels, Dr. Oscar J. Bienvenu and his colleagues wrote in the American Journal of Respiratory and Critical Care Medicine.

"Depressive symptoms may decrease motivation for and reward from the physical activities necessary for recovery of maintenance of functioning ... [they] can also amplify symptoms of general medical illnesses, and an increased physical symptom load could negatively affect functioning."

In addition, there may be less-understood links between depression and physical functioning, wrote Dr. Bienvenu of Johns Hopkins University, Baltimore, and his coauthors.

"Depressive symptoms could affect functioning through direct neurobiologic pathways, including neuroendocrine and inflammatory mechanisms."

The study comprised 2-year follow-up data on 186 patients. All of the patients were mechanically ventilated for acute lung injury (ALI). Baseline depression was present in 21% and baseline physical impairment in 40% (Am. J. Respir. Crit. Care Med. 2011 Dec. 8 [doi:10.1164/rccm.201103-0503OC]).

The patients’ mean age was 49 years; 56% were male. The mean length of stay in the intensive care unit (ICU) was 19 days. Patients were assessed for depression and physical function at 3, 6, 12, and 14 months after discharge.

During the entire follow-up period, 40% of the patients experienced new-onset depression and 66% had new-onset physical impairment. Remission occurred in 39% of those with depression and 54% of those with physical impairment, but there was recurrence in 20% and 14%, respectively. Most of those who developed depression or physical impairment had symptoms at 24 months (69% and 58%).

Patients who did remit, however, tended to do well. In those with remitted depression, the mean score on the Hospital and Anxiety Depression Scale remained about 5, indicating normal mood. In those whose symptoms did not remit, the score remained 10 or higher, indicating moderate to severe depression.

Similarly, those with remission of physical impairment had a mean of 1 impaired activity of daily living, compared with a mean of 4 or more in those with unremitted impairments.

When the authors looked at potential risk factors for new-onset depression and physical impairment, only two remained statistically significant in multivariate analyses. Education of 12 or fewer years increased the risk of new-onset depression by more than three times. Only depression at last follow-up significantly correlated with new-onset physical impairment (odds ratio, 2.7)

"Our analyses indicate that depressive symptoms are not only relatively persistent in ALI survivors, they are also an independent risk factor for subsequent impairment in physical function," the authors wrote. "Hence, early identification and treatment of depressive states should be evaluated as a potential intervention to minimize the suffering and impairment that affect too many of these patients."

The National Institutes of Health supported the study. None of the authors reported any financial conflicts.