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.