The ability of the Nottingham Hip Fracture Score to predict mobility, length of stay and mortality in hospital, and discharge destination in patients admitted with a hip fracture

The Nottingham Hip Fracture Score (NHFS) has been developed for predicting 30-day and 1-yr mortality after hip fracture. We hypothesise that NHFS may also predict other adverse events. Data from 666 patients (190 men, 476 women), aged 60.2-103.4yr, admitted with a hip fracture to a single centre from 1/10/2015 and 7/12/2017 were analysed. The ability of NHFS to predict mobility within 1-day after surgery, length of stay (LOS) and mortality, and discharge destination was evaluated by receiver operating characteristic curves and two-graph plots. The area under the curve (95% confidence interval [CI]) for predicting mortality was 67.4% (58.4-76.4%), prolonged LOS was 59.0% (54.0-64.0%), discharge to residential/nursing care was 62.3% (54.0-71.5%), and any two of failure to mobilise, prolonged LOS or discharge to residential/nursing care was 64.8% (59.0-70.6%). NHFS thresholds at 4 and 7 corresponding to the lower and upper limits of intermediate range where sensitivity and specificity equal 90% were identified for mortality and prolonged LOS, and 4 and 6 for discharge to residential/nursing care, which were used to create three risk categories. Compared with the low risk group (NHFS=0-4), the high risk group (NHFS=7-10 or 6-10) had increased risk of in-patient mortality: rates=2.0% versus 7.1%, OR (95%CI)=3.8 (1.5-9.9), failure to mobilise within 1-day of surgery: rates=18.9% versus 28.3%, OR=1.7 (1.0-2.8), prolonged LOS (>17days): rates=20.3% versus 33.9%, OR=2.2 (1.3-3.3), discharge to residential/nursing care: rates= 4.5% vs 12.3%, OR=3.0 (1.4-6.4), and any two of failure to mobilise, prolonged LOS or discharge to residential/nursing care: rates=10.5% versus 28.6%, 3.4 (95%CI = 1.9-6.0), and stayed 4.1days (1.5-6.7days) longer in hospital. High NHFS associates with increased risk of mortality, prolonged LOS and discharge to residential/nursing care, lending further support for its use to identify adverse events.