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. 2014 Sep;22(9):1241–1250. doi: 10.1016/j.joca.2014.07.006

Table III.

Univariable and multivariable survival models. HR are given for all-cause revision up to 8 years following surgery

Variable Univariable
Multivariable
HR (±95 CI) Significance HR (±95 CI) Significance
Age (linear, per year) 0.96 (0.96–0.97) <0.01 0.96 (0.96–0.97) <0.01
Gender (male) 0.83 (0.74–0.94) <0.01 0.86 (0.76–0.96) 0.01
ASA (per one grade increase) 0.94 (0.85–1.05) 0.27 1.06 (0.95–1.20) 0.30
BMI (per unit, n = 13,501) 1.02 (1.00–1.04) 0.05 1.01 (0.98–1.03) 0.59
Ethnic group – white Reference
un-defined 0.86 (0.72–1.02) 0.09 0.86 (0.72–1.02) 0.08
Mixed race 0.42 (0.07–2.65) 0.36 0.34 (0.05–2.24) 0.26
Asian 0.94 (0.60–1.46) 0.77 0.81 (0.52–1.25) 0.34
Black 1.39 (0.71–2.72) 0.33 1.02 (0.50–2.06) 0.96
Other 0.39 (0.09–1.61) 0.19 0.39 (0.09–1.61) 0.19
Unit type – NHS hospital Reference
Independent hospital 1.07 (0.88–1.30) 0.51 1.07 (0.87–1.30) 0.53
ISTC 1.10 (0.78–1.55) 0.59 1.43 (0.99–2.05) 0.05
Consultant performed 0.91 (0.77–1.07) 0.24 0.78 (0.67–0.91) <0.01
Mechanical thrombo-prophylaxis TEDS Reference
Foot pumps 1.02 (0.84–1.23) 0.87 0.98 (0.81–1.19) 0.82
Other 1.32 (0.80–2.18) 0.27 1.24 (0.77–2.01) 0.37
None 1.04 (0.85–1.27) 0.70 1.01 (0.83–1.22) 0.94
Chemical thrombo-prophylaxis Heparin/LMWH Reference
Aspirin 0.98 (0.79–1.22) 0.85 1.11 (0.90–1.37) 0.34
Warfarin 0.61 (0.30–1.26) 0.18 0.71 (0.35–1.44) 0.34
DTI 0.56 (0.30–1.04) 0.07 0.55 (0.30–1.01) 0.06
Other 0.86 (0.63–1.18) 0.36 0.81 (0.59–1.11) 0.19
None 1.15 (0.93–1.43) 0.20 1.22 (0.98–1.51) 0.08
Fixation 0.99 (0.77–1.26) 0.91 1.02 (0.79–1.31) 0.89
Charlson – No comorbidities Reference
Mild comorbidities 1.09 (0.94–1.27) 0.26 1.12 (0.96–1.30) 0.16
Moderate comorbidities 1.36 (0.95–1.95) 0.09 1.49 (1.04–2.12) 0.03
Severe comorbidities 1.21 (0.62–2.35) 0.58 1.40 (0.72–2.72) 0.33
IMD (per quintile) 0.91 (0.87–0.96) <0.01 0.96 (0.91–1.00) 0.07
Unit size (per ten cases) Up to 40 cases/yr 0.97 (0.96–0.99) <0.01 0.92 (0.86–0.97) 0.01
Above 40 cases/yr 0.99 (0.97–1.01 0.32

LMWH – low molecular weight heparin; DTI – direct thrombin inhibitor.