Incidence and risk factors of postoperative delirium after surgery in the spanish population: The DELPO study

Postoperative delirium increases morbidity, mortality, hospital stays, and costs, though 30-40 % of cases are preventable. This study assessed early delirium incidence in 2442 surgical patients across 43 Spanish hospitals, analyzing it by surgery type and related factors. Conducted from November 14 and 21, 2023, with follow-ups on days 2 and 60, it provides insights into factors influencing postoperative delirium and outcomes.

The study included three phases: (1) recruitment and assessment of surgical patients on November 14 and 21, 2023, across all centers; (2) monitoring for delirium by postoperative day 2; and (3) a follow-up at 60 days. Delirium was diagnosed using the CAM, CAM-ICU, and 4AT scales. The sample size was estimated and multivariable logistic regression and Cox regression analysis were performed to identify independent risk factors and assess the impact of delirium on mortality.

A total of 2442 surgical patients were recruited, mainly male (51.9 %), with a mean age of 76 ± 16 years. The delirium incidence was 3.93 %, with four preoperative independent risk factors identified through multivariate analysis.: Patient age (odds ratio (OR) 1.05, 95 % CI 1.04 to 1.08, p > 0.001), cognitive impairment (SBT > 6 points) (OR 1.12, 95 % CI 1.08 to 1.15, p < 0.001), substance use disorder (SUD) (OR 3.97, 95 % CI 1.05 to 14.93, p = 0.042) and alcoholism (OR 1.92, 95 % CI 1.20 to 3.07, p = 0.006), with a model AUROC of 0.81 (95 % CI 0.76 to 0.85). Postoperative delirium was associated with longer hospital stays and significantly higher mortality at 60 days (8.3 % vs 0.6 %).

This Spanish study found that postoperative delirium, linked to longer hospital stays and higher mortality, requires early detection and prevention to improve outcomes.