C-reactive protein predicts postoperative delirium following vascular surgery

Background: The etiology of postoperative delirium (POD) following vascular surgery is generally unknown. The incidence, however, can be as high as 35%. A possible neuroinflammatory basis for delirium is likely and C-reactive protein (CRP) as a marker for inflammation can possibly play a predictive role.

Methods: Between March 2010 and September 2012, 277 consecutive elective vascular surgery patients were prospectively evaluated for the diagnosis of POD. Various potential risk factors, including postoperative CRP values, were collected.

Results: The mean age of the patients was 69 ± 11 years (range 21-92). The mean hospital length of stay was 6 ± 4 days (range 1-33). Sixteen patients (6%) developed POD during hospital stay. Univariate analysis revealed multiple comorbidities (P = 0.001), postoperative elevated CRP levels (P = 0.001), intensive care unit admittance (P = 0.01), and open aortic surgery or amputation procedures (P = 0.0001) to be significantly related to the diagnosis POD. Multivariate logistic regression analysis confirmed the relationship between an elevated CRP value and POD (odds ratio [OR] 1.01, 95% confidence interval 1.00-1.03, P = 0.04). The sensitivity analyses yielded essentially similar results. Based on OR, it can be calculated that the risk of POD is increased by approximately 35% if the CRP concentration is 50 mg/L, and by approximately 90% if the CRP concentration is 100 mg/L (compared with a CRP concentration of 5 mg/L). Thirty-one percent (5/16) of patients with POD needed a long-stay care facility after discharge (P = 0.0001).

Conclusions: In this study, CRP can be used as a marker for an increased risk of POD after vascular surgery. In addition, it was found that POD was associated with a 10-fold increase in the need of long-stay care after discharge.