Delirium often occurs in older adults after hip fracture surgery. Anesthetic drugs have been linked with the development of postoperative delirium, but it's unclear whether the incidence of delirium is related to the use of regional or general anesthesia. A multicenter, randomized clinical trial was undertaken to determine whether regional anesthesia (spinal, epidural, or combined with no sedation) compared with general anesthesia (intravenous, inhalational, or combined) would reduce the incidence of postoperative delirium in older patients who had hip fracture surgery.

Patients who were age 65 or older undergoing surgical repair of a fragility hip fracture were eligible for the study. A total of 950 participants were randomly assigned to receive either regional or general anesthesia.

During the first seven postoperative days, delirium occurred in 29 (6.2%) patients who received regional anesthesia and 24 (5.1%) who received general anesthesia. The incidence of multiple episodes of delirium and hyperactive delirium was similar in the two groups, and there were no significant differences between the groups in the worst severity of delirium score, the worst pain score, length of hospitalization, and 30-day all-cause mortality. The overall rate of adverse events was also similar in the regional and general anesthesia groups.

The authors note that the incidence of postoperative delirium was lower than expected and likely attributable to predisposing factors related to age, physical status, culture, and health care systems, although missed diagnoses can't be ruled out. Also, most patients were recruited from the same hospital, which might have influenced the results.