The Clinical Frailty Scale is a valid and independent predictor of one-year survival in patients sustaining a hip fracture: scottish Hip Fracture Audit data from 8,092 patients

Aims: Hip fracture patients have a significant mortality risk. Risk stratification tools are important in guiding management and family discussions. Aims were to assess the associations and validity of the Clinical Frailty Scale (CFS) in predicting mortality and return to original residence within 30 days using national hip fracture registry data.

Methods: Routinely collected clinical registry data for all patients presenting with a hip fracture in Scotland aged 50 years and over between February 2022 and December 2023 with a completed CFS score were analyzed. The association of frailty with mortality and return to original residence was assessed using multivariable Cox regression and logistic regression analysis, respectively, adjusting for confounders to present adjusted hazard (aHRs) and odds ratios (aORs).

Results: Of 15,546 patients, 8,573 had completed the CFS. Exclusion for missingness gave a final sample of 8,092. Most (71.4%) were female with a median American Society of Anesthesiologists (ASA) grade of 3 (IQR 3 to 3) and CFS of 5 (IQR 4 to 7). Vulnerable and frail patients (CFS ≥ 4) were older, more likely to be admitted from a higher care setting, and had increased mortality risk on the same admission. Higher CFS scores were associated with increased mortality risk: mildly frail (CFS 4 to 5), aHR 1.67 (95% CI 1.53 to 1.87); and frail (CFS 6 to 8), aHR 3.01 (95% CI 2.59 to 3.50). CFS and ASA grade showed similar performance in predicting one-year mortality (CFS area under curve (AUC) 0.72, 95% CI 0.71 to 0.73; ASA AUC 0.66, 95% CI 0.65 to 0.67) and return to residence (CFS AUC 0.63, 95% CI 0.62 to 0.65; ASA AUC 0.61, 95% CI 0.60 to 0.62).

Conclusions: The CFS is a pragmatic and validated tool for assessing frailty, which has a strong association with mortality risk in patients with hip fractures. Its predictive accuracy supports its integration into national hip fracture registries. While its utility in predicting return to pre-injury residence is moderate, it remains a valuable component of comprehensive patient assessment.