Long-term Consequences of Postoperative Cognitive Dysfunction

Abstract

Background: Postoperative cognitive dysfunction (POCD) is common in elderly patients after noncardiac surgery, but the consequences are unknown. The authors' aim was to determine the effects of POCD on long-term prognosis. Methods: This was an observational study of Danish patients enrolled in two multicenter studies of POCD between November 1994 and October 2000. The cohort was followed up from the date of surgery until August 2007. Cognitive function was assessed by a neuropsychological test battery at three time points: before, at 1 week after, and at 3 months after noncardiac surgery. Data on survival, labor market attachment, and social transfer payments were obtained from administrative databases. The Cox proportional hazards regression model was used to compute relative risk estimates for mortality and disability, and the relative prevalence of time on social transfer payments was assessed by Poisson regression. Results: A total of 701 patients were followed up for a median of 8.5 yr (interquartile range, 5.3-11.4 yr). POCD at 3 months, but not at 1 week, was associated with increased mortality (hazard ratio, 1.63 [95% confidence interval, 1.11-2.38]; P = 0.01, adjusted for sex, age, and cancer). The risk of leaving the labor market prematurely because of disability or voluntary early retirement was higher among patients with 1-week POCD (hazard ratio, 2.26 [1.24-4.12]; P = 0.01). Patients with POCD at 1 week received social transfer payments for a longer proportion of observation time (prevalence ratio, 1.45 [1.03-2.04]; P = 0.03). Conclusions: Cognitive dysfunction after noncardiac surgery was associated with increased mortality, risk of leaving the labor market prematurely, and dependency on social transfer payments.