Preoperative Sleep Disturbance Linked to Higher Risk of Postoperative Delirium, suggests study

A new research published in the journal of BMC Surgery showed that elderly patients undergoing elective knee or total hip replacement surgery, preoperative sleep disturbance is independently associated with an increased risk of postoperative delirium (POD).

Postoperative delirium (POD) is a common neurocognitive disorder occurs after major surgical procedures, particularly in older adults. Symptoms may include confusion, disorientation, memory problems, agitation, and difficulty focusing. The condition is associated with longer hospital stays, increased healthcare costs, delayed recovery, and higher risks of long-term cognitive decline.

Despite sleep disturbance being frequently reported during the perioperative period, this study say its direct relationship with postoperative delirium has not been fully understood. Thus, this prospective cohort study involving 200 elderly patients undergoing elective total knee or hip replacement surgery between April and July 2025 was carried ahead.

Before surgery, participants completed the Pittsburgh Sleep Quality Index (PSQI), then monitored patients for signs of postoperative delirium twice daily during the first week after surgery using the Chinese version of the 3D Confusion Assessment Method (3D-CAM). The results showed that 35% of patients experienced significant preoperative sleep disturbance, while postoperative delirium developed in 14% of participants overall.

After adjusting for multiple factors including age, sex, anesthesia type, smoking, alcohol use, education level, body mass index, and existing medical conditions, this study found that poor sleep before surgery was independently associated with nearly a 3-fold increase in the risk of postoperative delirium. Statistical modeling also demonstrated a clear linear relationship between worsening sleep quality scores and increasing delirium risk.

These findings reinforce the growing understanding that sleep plays a crucial role in brain resilience and postoperative recovery. Sleep disruption may contribute to inflammation, stress hormone imbalance, altered neurotransmitter activity, and impaired cognitive regulation, all of which could increase vulnerability to delirium after surgery. Also, the relationship between poor sleep and delirium was more pronounced among patients younger than 80 years, women, individuals with normal body weight, and patients classified as ASA II (mild systemic disease).

Screening elderly surgical patients for sleep problems before surgery may help clinicians identify individuals at higher risk for postoperative delirium. Interventions aimed at improving sleep quality including sleep hygiene counseling, stress reduction strategies, or optimization of sleep-related medical conditions, could potentially become part of preoperative preparation protocols. Overall, the findings suggest that identifying modifiable risk factors such as sleep disturbance could help improve perioperative care and reduce complications.

Reference:

Han, J., Yang, Q., Zhao, Y., Chen, L., Wang, Z., Zhu, J., Su, X., & Tian, S. (2026). Preoperative sleep disturbance and postoperative delirium in elderly joint replacement patients: a prospective cohort study. BMC Surgery. https://doi.org/10.1186/s12893-026-03797-0