OBJECTIVE : The aim of this study was to define the prevalence of preexisting mental illness, as well as characterize the impact of a preexisting mental illness diagnosis on postoperative outcomes.

SUMMARY BACKGROUND DATA : Preoperative surgical evaluation and risk stratification have traditionally centered on optimizing physical health. The influence of mental health on postoperative surgical outcomes has not been investigated.

METHODS : Medicare beneficiaries who underwent elective colectomy, coronary artery bypass grafting, abdominal aortic aneurysm repair, abdominal aortic aneurysm repair, total hip arthroplasty, total knee arthroplasty, and lung resection were identified. Patients were classified as having mental illness using International Classification of Diseases, 9 and 10 Revisions Procedures codes (ICD9/10CM) codes for anxiety, depression, bipolar disorder, schizophrenia, or other psychotic disorder.

RESULTS : Among 1,889,032 Medicare beneficiaries who met inclusion criteria 560,744 (n = 29.7%) individuals had an antecedent diagnosis of mental illness. The majority had anxiety and/or depression (91.8%), whereas a smaller subset (8.2%) had a severe mental illness diagnosis. Patients who did and did not have mental illness were comparable relative to age and comorbidities. Patients with preoperative mental illness had a higher chance of surgical complications [anxiety/depression odds ratio (OR) 1.44, 95% confidence interval (CI) 1.42-1.46, severe mental illness OR 1.71, 95%CI 1.66-1.77] and an extended length of stay (anxiety/depression OR 1.45, 95% CI 1.44-1.46, severe mental illness OR 2.34, 95% CI 2.28-2.39). History of anxiety/depression (OR 1.87, 95% CI 1.85-1.90) or severe mental illness (OR 2.86, 95% CI 2.77-2.94) was also associated with higher odds of 30-day readmission. Additionally, individuals with mental illness had a higher prevalence of suicidal ideation within the first year after surgery (no mental illness: 1.88 per 100,000 individuals; anxiety/depression: 51.3 per 100,000 individuals; severe mental illness: 238.9 per 100,000 individuals).

CONCLUSIONS : Three in 10 Medicare beneficiaries had a preexisting mental illness diagnosis, which was strongly associated with worse postoperative outcomes, as well as suicide risk. Surgeons need to optimize mental health assessment and services in the preoperative setting to improve outcomes for this vulnerable population.