Table 2

Effect of proportion of late surgery patients on mortality in different severity groups of hip fracture patients

n (%)One year mortalitySlope*(p value)
10% of patients with late surgery15% of patients with late surgery20% of patients with late surgery30% of patients with late surgery
*Change in percentage of deaths when the share of patients with late surgey increased 10%.
†Corresponds to fig 4. Example: Expected mortality for late surgery patients in provider with 10% of patients with late surgery is 35%. These percentages can be interpreted as coordinates (0.10, 0.35) which hit the dotted curve in fig 4.
‡Calculated from the equation: ml(X)  =  (m(X) − (1−X) * me(X))/X, where X is the proportion of late surgery patients, m(X) refers to overall mortality at X, me(X) to early surgery mortality at X, and ml(X) to late surgery mortality at X. Example: ml(0.1)  =  (0.2903 − 0.9 * 0.2837)/0.1  =  0.3497.
Overall1688129.029.329.530.00.5 (<0.05)
Early surgery14426 (85)28.428.829.330.20.9 (<0.01)
Late surgery‡2455 (15)35.0‡31.930.529.7
Patient group 1 (least severe)
Overall3376 (20)9.49.39.29.0−0.2 (0.232)
Early surgery2931 (87)8.88.68.48.1−0.3 (0.168)
Late surgery445 (13)15.413.412.411.1
Patient group 2
Overall3376 (20)18.017.917.817.6−0.2 (0.283)
Early surgery2932 (87)17.417.517.717.90.2 (0.310)
Late surgery444 (13)23.820.118.416.7
Patient group 3
Overall3376 (20)26.927.227.628.20.6 (0.101)
Early surgery2875 (85)26.627.528.530.41.9 (<0.01)
Late surgery501 (15)29.725.423.823.1
Patient group 4
Overall3377 (20)37.938.338.739.50.8 (0.126)
Early surgery2869 (85)37.438.339.241.11.8 (<0.05)
Late surgery508 (15)43.038.536.735.8
Patient group 5 (most severe)
Overall3376 (20)51.451.952.553.51.1 (<0.05)
Early surgery2819 (84)50.750.650.650.5−0.1 (0.455)
Late surgery557 (16)57.959.359.960.6