Anticholinergic burden of long-term medication is an independent risk factor for the development of postoperative delirium: A clinical trial

Postoperative delirium (POD) is a common complication after surgery. We sought to determine the association between preoperative anticholinergic load calculated using the anticholinergic drug scale (ADS) and POD in cancer patients over 65 years of age. A retrospective sub-investigation of a randomised controlled interventional trial. Two tertiary university hospitals. Overall, patients aged 65 years and older scheduled for surgical treatment of gastrointestinary, genitourinary or gynaecological cancers. The primary outcome was the interaction between anticholinergic drug scale and occurrence of postoperative delirium. Patient clinical parameters and ADS scores were assessed preoperatively. POD screening was conducted for a total of 7 days following surgery using validated measures. Independent associations between ADS and POD were assessed using multivariate logistical regression analyses. A total of 651 patients (mean age, 71.8 years; 68.5% males) were included. Of those, 66 patients (10.1%) developed POD. The ADS score was independently associated with the occurrence of POD (higher ADS per point OR 1.496; 95% CI 1.09–2.05; p = 0.01). Additionally, age (per year OR 1.06; CI 95% CI 1.01–1.11; p = 0.03) and ASA state (OR 2.16; 95% CI 1.22–3.83; p = 0.01), as well as stay on ICU (yes vs. no OR 2.8; 95% CI 1.57–4.998; p < 0.01), were independently associated with POD. ADS assessment according to chronic medication use is a cost-effective, non-invasive method of identifying elderly cancer patients at risk for POD. Trial registry: www.clinicaltrials.gov. Identifier NCT01278537. Ethics: IRB of Charité University-Medicine Berlin, Germany; EA2/241/08.