Validation of a prospective mortality prediction score for hip fracture patients

Although mortality prediction tools are the subject of significant interest as components of comprehensive hip fracture protocols, few have been applied or validated to prospectively inform ongoing patient management. Five regional hospitals are currently generating real-time mortality risk scores for all adults at the time of admission using available laboratory and comorbidity data (Cowen et al. J Hosp Med 9(11):720-726, 2014). Although results for aggregated conditions have been published, the primary aim of this study is to determine how well prospectively calculated scores predict mortality for hip fracture patients specifically.

Using a five-hospital database, 1376 patients who were prospectively scored on admission were identified from January 2013 to April 2017, cross-referencing ICD9/10 diagnosis and procedure codes for AO/OTA 31A1 through 31B3 fractures. Prospective mortality scores have been previously divided into 5 risk categories to facilitate ease of clinical use. Vital status was determined from hospital data, Social Security and Michigan Death Indices.

Prospective scores demonstrated good mortality prediction, with AUCs of 0.80, 0.73, 0.74 and 0.74 for in hospital, 30-, 60- and 90-day mortality, respectively. Patients in the top 2 mortality risk categories represented 30% (410/1376) of the cohort and accounted for 78% (25/32) of the inpatient and 59% (57/97) of the 30 day deaths.

Implementation of this real-time mortality risk tool is feasible and valid for the prediction of short- to medium-term mortality risk for hip fracture patients, and potentially offers valuable information to guide ongoing patient management decisions such as admitting service or level of care.