Frailty and intraoperative hypotension in older adults undergoing hip fracture surgery: a retrospective cohort study

Frailty is common among older adults and is associated with adverse postoperative outcomes. Hip fractures are increasingly prevalent in aging populations and frequently require urgent surgical intervention. Intraoperative hypotension (IOH) is a common perioperative complication associated with serious postoperative morbidity. However, the relationship between frailty and IOH remains unclear. This study aimed to investigate the association between frailty, assessed using the 11-item modified frailty index (mFI-11), and IOH in older adults undergoing hip fracture surgery. This retrospective cohort study included 522 patients aged ≥ 65 years who underwent hip fracture surgery at a tertiary care hospital in southern Thailand between January 2019 and June 2024. Patients were classified as frail (mFI-11 ≥ 0.27), prefrail (> 0 to < 0.27), or robust (0). IOH was defined as a mean arterial pressure (MAP) < 65 mmHg or a ≥ 20% reduction from baseline MAP in patients with hypertension. Multivariable logistic regression was used to evaluate the association between frailty and IOH. Adjusted quantile regression was performed to assess the association between frailty and cumulative duration of IOH. Among 522 patients, 124 (23.8%) were classified as frail, 341 (65.3%) as prefrail, and 57 (10.9%) as robust. IOH occurred in 298 patients (57.1%). Frailty was not independently associated with IOH. Compared with robust patients, the adjusted odds ratios for IOH were 0.78 (95% CI 0.42–1.43) for prefrail patients and 0.77 (95% CI 0.38–1.53) for frail patients. Independent predictors of IOH included intertrochanteric fracture, general anesthesia, preoperative antihypertensive medication administration on the day of surgery, longer operative duration, and colloid infusion. The multivariable model demonstrated modest discrimination (AUC 0.665, 95% CI 0.618–0.713). Although the incidence of IOH was similar across frailty groups, frail patients experienced longer cumulative duration of IOH. In adjusted analyses, frail patients had longer cumulative duration of IOH than prefrail patients ( p = 0.045). Overall postoperative complication rates were similar among groups. Frailty assessed using the mFI-11 was not independently associated with IOH occurrence in older adults undergoing hip fracture surgery. However, frail patients tended to experience a longer cumulative duration of IOH once it developed, suggesting a possible link between frailty and the persistence rather than the occurrence of intraoperative hemodynamic instability. These findings highlight the importance of vigilant intraoperative hemodynamic monitoring and individualized perioperative management in frail older adults.