Depressive symptoms and impaired physical function were common and long-lasting during the first two years following acute lung injury (ALI), according to a new study from Johns Hopkins University School of Medicine. Depressive symptoms were an independent risk factor for impaired physical function.

"Early identification and treatment of depressive states should be evaluated as a potential intervention to improve long-term outcomes in ALI survivors," said first author O. Joseph Bienvenu, M.D., Ph.D., associate professor of psychiatry and behavioral sciences. "Depressive symptoms are a potentially modifiable risk factor for later-onset physical impairment in these patients."

The findings were published online ahead of print publication in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

A total of 186 mechanically ventilated patients with ALI were included in the study, with follow-up at 3, 6, 12 and 24 months following injury. Outcome measures included the Hospital Anxiety and Depression Scale (HADS), with a score ≥8 indicating depressive symptoms, and dependencies in instrumental activities of daily living (IADLs), with ≥2 impairments indicating impaired physical function.

The cumulative two-year incidence of depressive symptoms among the 147 patients without baseline depression was 40 percent, and the cumulative incidence of impaired physical function among the 112 patients without baseline impaired physical function was 66 percent. Incidence rates were highest at three-month follow-up and declined thereafter. The modal (most common) durations were >21 months for each outcome. In multivariable analyses, an education ≤12 year was significantly associated with incident depressive symptoms, and depressive symptoms at last follow-up were significantly associated with incident impaired physical function.

There were some limitations to the study. Depressive symptoms were measured using a self-report questionnaire, not psychiatric diagnoses. Baseline depression was identified from medical records, which may have led to some inaccuracy regarding patients' baseline mood states. Lastly, the possible effects of treatment of depression or impaired physical function were not considered, and instances of depressive symptoms or impaired physical function that occurred but resolved may have been missed.

"Depressive symptoms are not only persistent in ALI survivors but are a risk factor for subsequent impairment in physical function in ALI survivors," said last author Dale M. Needham, M.D., Ph.D., associate professor of pulmonary and critical care medicine. "Given our findings, the early identification and treatment of depressive symptoms should be evaluated as part of the comprehensive rehabilitation of these patients, to determine if such an intervention would improve not only mood states but physical functioning."