How do commonly used risk assessment scores compare in predicting perioperative outcomes following hip fracture surgery?

Introduction:

Hip fractures are associated with significant mortality, prolonged hospital admission and loss of independence in older adults. Several risk assessment scores, including the Clinical Frailty Scale (CFS), American Society of Anaesthesiologists (ASA) grade, Nottingham Hip Fracture Score (NHFS) and RHMP30 score, are used to estimate patient risk. This study compared the association between these scoring systems and clinically relevant outcomes following hip fracture surgery to explore whether any score demonstrated a more consistent relationship with patient outcomes.

Methods:

A retrospective cohort study of 100 consecutive adults undergoing hip fracture surgery between March and May 2026 at a UK hospital was undertaken. CFS, ASA grade, NHFS and RHMP30 were recorded for each patient. Outcomes included inpatient mortality, 30-day mortality, length of stay and return to usual residence. Patients were grouped according to each scoring system, and outcomes were compared across the different risk categories.

Results:

Higher CFS, ASA grade, NHFS and RHMP30 scores were all associated with increasing 30-day mortality. Thirty-day mortality increased from 0% in CFS 1–4 to 23.8% in CFS 6, from 0% in ASA 2 to 18.2% in ASA 4, and from 0% in RHMP30 decile 1 to 30% in decile 10. Similar trends were observed across increasing NHFS categories. Associations with return to usual residence and length of stay were generally weak or inconsistent across all four scoring systems, suggesting these outcomes are influenced by factors beyond physiological risk alone.

Conclusions

All four risk assessment scores demonstrated an association with 30-day mortality following hip fracture surgery. However, associations with return to usual residence and length of stay were weaker and less consistent in this cohort. The weak association with length of stay may reflect the influence of discharge pathways and rehabilitation needs, rather than patient risk alone.