The study objective was to measure the prevalence and predictors of cognitive impairment (CI) and delirium.

Adults undergoing major head and neck cancer surgery completed the Clock Draw Test to screen for CI, defined as a score of 0 or 1. Postoperative delirium was recorded.

Predictors of delirium and length of stay were assessed by univariate logistic regression and the latter with multivariate linear regression.

Overall 274 patients were included, of which 47% had a Clock Draw Test score of 0 or 1. Post-operative delirium occurred in 17 (6%). CI was a predictor of postoperative delirium (odds ratio, 3.9; 95% CI, 1.2-12; P = .02).

Postoperative delirium was a predictor of increased length of stay (adjusted odds ratio, 1.30; 95% CI, 1.07-1.57; P = .0073) on multivariate regression while baseline Clock Draw Test result was not a predictor on univariate regression (P = .98). Screening for CI can help predict delirium and facilitate targeted interventions in the postoperative period.