Impact of serious mental illness on surgical patient outcomes.

Background: People with comorbid mental illness have poorer health status and disparate access to healthcare. Several studies internationally have reported mixed findings regarding the association between mental illness and surgical patient outcomes. This study examines the surgical outcomes in people with decompensated serious mental illness (SMI) within the setting of the Australian universal healthcare system.

Methods: Retrospective cohort study involving elective overnight surgical patients aged 18 years and above who attended a large public tertiary referral hospital in Sydney, Australia, between 2010 and 2014. Patients were identified using ICD-10-AM diagnosis codes. Outcomes measure including in-hospital mortality, post-operative complications, morbidity, admission and time in intensive care, length and cost of hospitalization, discharge destination and 28-day re-admission rates were examined.

Results: Of 23 343 surgical patient admissions, 451 (2%) patients had decompensated comorbid SMI with a subset of 47 (0.2%) having a specific psychotic illness. Patients with SMI comorbidity had significantly higher in-hospital mortality (2% versus 0%), post-operative complications (22% versus 8%), total comorbidity (7.6 versus 3.4 secondary codes), admissions (29% versus 9%) and time in intensive care (34.6 h versus 5.0 h), stay in hospital (12.2 days versus 4.6 days), admission costs ($24 162 versus $12 336), re-admission within 28 days (14% versus 10%) and discharges to another facility (11% versus 3%).

Conclusion: Patients with comorbid SMI had significantly worse surgical outcomes and incur much higher costs compared with the general surgical population. These results strongly highlight that specific perioperative interventions are needed to proactively improve the identification, management and outcomes for these disadvantaged patients.