Risk factors for new antidepressant use after surgery in Sweden: a nationwide, observational cohort study

Background: Whilst somatic complications after major surgery are being increasingly investigated, the research field has scarce data on psychiatric outcomes such as postoperative depression. This study evaluates the impact of patient and surgical factors on the risk of depression after surgery using the proxy measure of prescribed and collected antidepressants. Methods: An observational, registry-based, national multicentre cohort study of individuals ≥18 yr of age who underwent noncardiac surgery between 2007 and 2014. Exclusion criteria included history of antidepressant use defined by collection of a prescription within 5 yr before surgery. Participants were identified using a surgical database from 23 Swedish hospitals and data were linked to National Board of Health and Welfare registers for collection of prescribed antidepressants. Descriptive statistics were used for baseline data and logistic regression for predictive factors. Results: Of 223 617 patients, 4.9% had a new prescription of antidepressants collected 31-365 days after surgery. Antidepressant prescription was associated with increasing age, female sex, and more comorbidities. The incidence of antidepressant prescription was highest after neurosurgery, vascular, and thoracic surgery. Affective and anxiety disorders were risk factors. In the whole cohort and within the aforementioned surgical subtypes, acute and cancer surgery increased the risk of antidepressant prescription. Conclusions: This study brings novel insights to the epidemiology of postoperative antidepressant treatment in antidepressant-naive patients. One in 20 postoperative patients are prescribed antidepressants but with knowledge of risk factors, interventional strategies can be tested.