TUESDAY, Oct. 19 (HealthDay News) -- People with depression and anxiety have a slightly increased risk of death after undergoing surgery, a new study suggests.

U.S. researchers analyzed data from 35,539 surgical patients admitted to intensive care units between Oct. 1, 2003 and Sept. 30, 2006. Of those patients, 8,922 (25.1 percent) had an existing psychiatric condition, including 5,500 (15.5 percent) with depression, 2,913 (8.2 percent) with post-traumatic stress disorder, 2,473 (7 percent) with anxiety, 793 (2.2 percent) with bipolar disorder, and 621 (1.8 percent) with psychosis.

Initial analysis showed that the death rates within 30 days after surgery were similar for patients with and without psychiatric illness -- 3.8 percent and 4 percent, respectively. But when the researchers adjusted for other factors, the death rate was higher for patients with a psychiatric condition, according to the report in the October issue of the journal Archives of Surgery.

Further analysis showed that the increased risk of death was associated with depression and anxiety, but not any other psychiatric condition. Also, death rates were higher among patients with psychiatric conditions who had respiratory or digestive system surgery, but not for those who had surgery involving the circulatory, nervous or musculoskeletal systems.

"Several potential mechanisms exist to explain these findings," Dr. Thad E. Abrams, of the Iowa City Veterans Affairs Medical Center and University of Iowa Carver College of Medicine in Iowa City, and colleagues wrote in a news release from the journal's publisher.

"First, studies indicate that patients with depression frequently do not adhere to medical recommendations for underlying medical conditions," the study authors noted. "It is therefore plausible that such undertreated conditions may affect postoperative care and outcomes. Second, patients with existing psychiatric comorbidity may be more likely to undergo surgery by a lower-quality surgeon or hospital. Third, pre-existing psychiatric comorbidity may serve as an indicator for greater severity of surgical risk."

The findings suggest that surgical patients with depression or anxiety require special care.

"Until further research is completed, we recommend that surgeons caring for patients with a history of anxiety or depression seek early involvement of multidisciplinary teams to help identify problematic areas in perioperative care processes, particularly regarding issues of surgeon-patient communication and adherence to post-surgical recommendations," Abrams and colleagues concluded.

More information

The Anxiety Disorders Association of America has more about anxiety and depression.