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.

Inclusion criteria:

1. Aged ≥65 years;
2. Scheduled for elective non-cardiac, non-neurosurgical procedures;
3. Consented to undergo preoperative health and functional state assessments.

Exclusion criteria:

1. Had severe dementia, language disorders, significant hearing or visual impairments, or were in a coma;
2. Had Mini-Mental State Examination (MMSE) scores below the established educational thresholds: <18 for illiterate individuals, <21 for those with primary education (≤6 years), and <25 for those with secondary education or higher (>6 years)
3. Underwent local anesthesia or monitored anesthesia care;
4. Had an operative time ≤30 minutes;
5. Incomplete preoperative FRAIL scale assessment;
6. Missing postoperative delirium data;
7. Incomplete FRAIL scale assessment at 1 month postoperatively.

Patients were divided into postoperative delirium (POD) and non-POD groups based on delirium occurrence within 7 days after surgery. Follow-up assessments were conducted at 30 days and 1 year postoperatively to evaluate frailty change and survival outcomes.