Association between sedation during spinal anesthesia and mortality in older patients undergoing hip fracture surgery: A nationwide retrospective cohort study in Japan

Intraoperative sedation plays an important role in the management of regional anesthesia. Few studies have investigated the association of sedation during spinal anesthesia with postoperative mortality in older patients as a primary outcome. This study aimed to test the hypothesis that sedation during spinal anesthesia increases postoperative mortality in older patients undergoing hip fracture surgery.Retrospective, cohort study.Acute and subacute care hospitals in Japan.Patients aged 65 years and older who received hip fracture surgery under spinal anesthesia between April 2014 and May 2022.Sedation during spinal anesthesia.Postoperative in-hospital all-cause mortality within 30 days.In total, 25,554 eligible patients were identified. Propensity score matching created 4735 pairs, and baseline patient characteristics were acceptably balanced between the sedation and non-sedation groups. There was no significant difference in 30-day postoperative mortality between the two groups (hazard ratio [95% CIs]: 0.92 [0.59-1.44]).There was no association between sedation during hip fracture surgery in older patients under spinal anesthesia and postoperative mortality. However, these results are limited to our population, and further prospective studies are needed to determine the safety of sedation.