Influence of psychiatric comorbidity on surgical mortality

Abstract

Objective: To examine the potential effect of 5 existing psychiatric comorbidities on postsurgical mortality.

Design: Retrospective cohort.

Setting: Intensive care units of all Veterans Health Administration hospitals designated as providing acute care.

Patients: We studied 35 539 surgical patients admitted to intensive care units from October 1, 2003, through September 30, 2006.

Main outcome measures: Psychiatric comorbidity (depression, anxiety, posttraumatic stress disorder, bipolar disease, and schizophrenia) was identified using outpatient encounters in the 12 months preceding the index admission. End points included in-hospital and 30-day mortality. Generalized estimating equations accounted for hospital clustering and adjusted mortality for demographics, type of surgery, medical comorbidity, and disease severity.

Results: We identified 8922 patients (25.1%) with an existing psychiatric comorbidity on admission. Unadjusted 30-day mortality rates were similar among patients with and without psychiatric comorbidity (3.8% vs 4.0%, P = .56). After adjustment, 30-day mortality was higher for patients with psychiatric comorbidity (odds ratio, 1.21; 95% confidence interval, 1.07-1.37; P = .003). In individual analyses, patients with depression and anxiety had higher odds of 30-day mortality (P = .01 and P = .02, respectively) but the odds were similar for the other conditions.

Conclusion: Existing psychiatric comorbidity was associated with a modest increased risk of death among postsurgical patients. Estimates of the increased risk across the individual conditions were highest for anxiety and depression. The higher mortality may reflect higher unmeasured severity or unique management issues in patients with psychiatric comorbidity.