Cognitive dysfunction 1-2 years after non-cardiac surgery in the elderly

Background: Postoperative cognitive dysfunction (POCD) is a well-recognised complication of cardiac surgery, but evidence of POCD after general surger y has been lacking. We recently showed that POCD was present in 9.9% of eld erly patients 3 months after major non-cardiac surgery. The aim of the pres ent study was to investigate whether POCD persists for 1-2 years after oper ation. Methods: A total of 336 elderly patients (median age 69 years, range 60-86) was studied after major surgery under general anesthesia. Psychometric tes ting was performed before surgery and at a median of 7, 98 and 532 days pos toperatively using a neuropsychological test battery with 7 subtests. A con trol group of 47 non-hospitalised volunteers of similar age were tested wit h the test battery at the same intervals. Results: 1-2 years after surgery, 35 out of 336 patients (10.4%, CI: 7.2-13 .7%) had cognitive dysfunction. Three patients had POCD at all three postop erative test sessions (0.9%). From our definition of POCD, there is only a 1:64 000 likelihood that a single subject would have POCD at all three test points by chance. Logistic regression analysis identified age, early POCD, and infection within the first three postoperative months as significant r isk factors for long-term cognitive dysfunction. Five of 47 normal controls fulfilled the criteria for cognitive dysfunction 1-2 years after initial t esting (10.6%, CI: 1.8-19.4%), i.e. a similar incidence of age-related cogn itive impairment as among patients. Conclusion: POCD is a reversible condition in the majority of cases but may persist in approximately 1% of patients.