Associations of postoperative delirium with perioperative frailty worsening and their combined effect on 1-year mortality in older surgical patients: a prospective cohort study

To determine whether postoperative delirium (POD) accelerates perioperative frailty worsening in older surgical patients and how their combined effect influences long-term survival. POD was independently associated with a higher risk of perioperative frailty worsening. Both POD and frailty worsening predicted increased 1-year mortality, and their coexistence conferred the greatest mortality risk. Early identification and management of POD may help slow frailty progression and improve survival in older surgical patients. Postoperative delirium (POD) is a frequent complication in older surgical patients and is associated with adverse outcomes, while frailty is also highly prevalent during the perioperative period. This study aimed to determine whether POD accelerates perioperative frailty worsening and to assess the effect of their coexistence on 1-year mortality. We analyzed prospectively collected data from a multicenter cohort of patients aged ≥65 years undergoing non-cardiac, non-neurosurgical surgery. Frailty was assessed using the FRAIL scale before surgery and at 1 month postoperatively. Perioperative frailty worsening was defined as an increase in the postoperative score compared with the preoperative score. POD was diagnosed using the 3-Minute Diagnostic Interview for Confusion Assessment Method. Logistic regression was employed to examine the associations between POD and frailty worsening, as well as the combined effect of their coexistence on 1-year mortality. Subgroup analysis was performed to confirm the robustness of the findings. Of the 6196 patients included, 648 (10.5%) developed POD. Perioperative frailty worsening occurred more frequently in patients with POD compared with those without (41.7% vs. 28.5%, P < 0.001). POD was independently associated with frailty worsening (OR 1.851, 95%CI 1.541–2.224; P < 0.001). Both POD and frailty worsening were independently associated with increased 1-year mortality. Compared with other groups, patients with both conditions had the highest 1-year mortality (5.9%), and this combination remained an independent predictor of mortality (OR 3.626, 95%CI 1.987–6.615; P < 0.001). POD accelerates perioperative frailty worsening in older surgical patients, and their coexistence substantially increases 1-year mortality risk. Early recognition and proactive management of POD may help mitigate frailty progression and improve long-term survival.