Study quantifies link between preoperative depression, postoperative delirium

Editor's Note

Individuals with preoperative depression are at significantly higher risk of developing postoperative delirium, according to a systematic review and meta-analysis of 42 studies involving a total of 4.6 million patients. Published September 4 in Anaesthesia, the study is first review to quantify the incidence and risk of postoperative delirium in a generalized cohort of patients with pre-operative depression undergoing major surgery.

Across the studies analyzed, the incidence of postoperative delirium among patients with pre-operative depression was 29%, compared to 15% in patients without depression. The review also found a strong association between pre-operative depression and postoperative delirium, with patients with depression nearly twice as likely to develop delirium. This increased risk was consistent across a variety of surgery types, including cardiac and non-cardiac procedures, and across older and younger adult populations.

Risk was highest in specific subgroups. For example, both cardiac surgery patients and older adults (aged 65 and above) showed a 41% incidence of postoperative delirium. The use of validated screening instruments to assess depressive symptoms before surgery also revealed a higher pooled incidence of delirium compared to studies relying on medical history or diagnostic codes alone, researchers write.

The review underscores the complex relationship between depression and postoperative delirium, which may stem from shared neurophysiological pathways involving stress responses, neurotransmitter imbalances, and inflammation, researchers conclude.  Given that postoperative delirium is linked to longer hospital stays, functional decline, cognitive impairment, and increased mortality, the findings suggest that improving the identification and management of depression could reduce complications and improve outcomes for surgical patients. They advocate for routine screening of depressive symptoms using formal assessment tools, as well as the development of multimodal interventions to reduce the risk of delirium in patients with psychiatric comorbidities.