Pre-operative inflammatory markers and the risk of postoperative delirium in elderly patients

Objective Pathophysiological mechanisms leading to delirium are not clear. Age is a known risk factor and hypothesised to be accompanied by a low-grade inflammatory state. Previous studies have shown an association between delirium and circulating proinflammatory markers in acutely ill and postoperative patients. In light of the ageing/inflammation theory, we investigated the association of these markers with delirium in not acutely ill, elderly patients. Methods In a prospective nested case-control study levels of C-reactive protein (CRP), interleukin 6 (II-6), insulin growth factor I (IGF-1) were measured pre-operatively in elderly patients admitted for hip-surgery. These levels were compared between patients who later developed a post-operative delirium and patients who did not. Patients were matched for age and disease severity. Results Eighteen patients who developed delirium post-operatively were matched with 50 controls. Median APACHE-scores were below 16 in both groups. Pre-operative serum concentrations of CRP, II-6 and IGF-1 did not differ between groups. IL-6 levels were associated with a measure of cognitive impairment. Conclusion In the present study no relationship was found between levels of pre-operative circulating pro-inflammatory markers and post-operative delirium in elderly patients, who were free from acute or severe disease. Copyright (c) 2008 John Wiley & Sons, Ltd.