External Validation of Ten Prediction Models for 30-day Mortality Following Hip Fracture

Hip fractures are a major health concern, especially among older adults, and are associated with substantial morbidity, mortality, and healthcare costs. While surgical intervention is standard practice for most patients, a growing number of cases require careful consideration of operative versus non-operative management based on individual risk profiles and patient preferences.

Several prediction models have been developed to estimate the risk of short-term mortality after hip fracture, but many have shown only moderate predictive performance or lacked clinical applicability. In 2024, a systematic review identified ten models with a low risk of bias, based on methodological criteria such as adequate sample size, proper handling of missing data, internal validation, and assessment of calibration.

This study aims to externally validate these ten prediction models using data from the Dutch Hip Fracture Audit (DHFA) combined with additional structured and unstructured clinical information extracted through CTcue, a text-mining software tool. Approximately 35 variables, including key preoperative factors such as age, sex, ASA score, institutionalization, and metastatic cancer, will be analyzed. Missing data will be addressed through multiple imputation.

The primary outcome is 30-day all-cause mortality following a hip fracture. Validation of the models will involve evaluation of predictive performance through discrimination (area under the curve [AUC]), explained variance (R²), and calibration curves. The DeLong test will be used to statistically compare model AUCs. Clinical usefulness will be assessed by calculating Net Benefit and conducting Decision Curve Analysis.

By rigorously validating these models in a large, real-world cohort, the study aims to identify which models offer both strong predictive accuracy and practical feasibility for supporting shared decision-making between clinicians and patients.

Inclusion criteria

• Patients admitted to OLVG between January 1, 2016, and March 1, 2024, with a diagnosis of hip fracture; and/or.
• Patients who underwent surgery at OLVG between January 1, 2016, and March 1, 2024, with an indication of hip fracture; and.
• Availability of independent predictor variables for at least one of the selected prediction models in the medical record.

Exclusion criteria

• Patients with unknown 30-day follow-up mortality status.
• Patients with periprosthetic fractures (fractures around an existing hip prosthesis) at the time of presentation.
• Patients aged under 18 years at the time of hip fracture.
• Patients who declined the use of their medical data for research purposes.