External validation of the Hospital Frailty Risk Score in France

Background: The Hospital Frailty Risk Score (HFRS) has made it possible internationally to identify subgroups of patients

with characteristics of frailty from routinely collected hospital data.

Objective: To externally validate the HFRS in France.

Design: A retrospective analysis of the French medical information database.

Setting: 743 hospitals in Metropolitan France.

Subjects: All patients aged 75 years or older hospitalised as an emergency in 2017 (n = 1,042,234).

Methods: The HFRS was calculated for each patient based on the index stay and hospitalisations over the preceding 2 years.

Main outcome measures were 30-day in-patient mortality, length of stay (LOS) >10 days and 30-day readmissions. Mixed

logistic regression models were used to investigate the association between outcomes and HFRS score.

Results: Patients with high HFRS risk were associated with increased risk of mortality and prolonged LOS (adjusted odds

ratio [aOR] = 1.38 [1.35–1.42] and 3.27 [3.22–3.32], c-statistics = 0.676 and 0.684, respectively), while it appeared less

predictive of readmissions (aOR = 1.00 [0.98–1.02], c-statistic = 0.600). Model calibration was excellent. Restricting the

score to data prior to index admission reduced discrimination of HFRS substantially.

Conclusions: HFRS can be used in France to determine risks of 30-day in-patient mortality and prolonged LOS, but not

30-day readmissions. Trial registration: Reference ID on clinicaltrials.gov: ID: NCT03905629.