EQ-5D utility, costs and estimated QALYs for subgroups with different baseline OKS
| OKS decile | 10 (worst) | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 (best) | All patients |
| Baseline OKS range | <9 | 9–11 | 12–13 | 14–15 | 16–17 | 18–19 | 20–21 | 22–24 | 25–27 | >27 | 0–48 |
| No. of KAT participants | 204 | 213 | 186 | 232 | 193 | 224 | 195 | 256 | 194 | 234 | 2131 |
| EQ-5D utility (SE)* | |||||||||||
| Baseline | 0.03 (0.004) | 0.14 (0.005) | 0.21 (0.006) | 0.25 (0.006) | 0.36 (0.006) | 0.46 (0.006) | 0.55 (0.005) | 0.57 (0.004) | 0.61 (0.004) | 0.67 (0.003) | 0.39 (0.002) |
| 3 months | 0.54 (0.007) | 0.58 (0.006) | 0.64 (0.006) | 0.66 (0.005) | 0.71 (0.005) | 0.71 (0.005) | 0.70 (0.004) | 0.74 (0.004) | 0.75 (0.005) | 0.77 (0.004) | 0.68 (0.002) |
| 1 year | 0.51 (0.007) | 0.60 (0.007) | 0.68 (0.006) | 0.70 (0.006) | 0.71 (0.006) | 0.75 (0.005) | 0.69 (0.006) | 0.78 (0.004) | 0.79 (0.005) | 0.84 (0.004) | 0.71 (0.002) |
| 2 year | 0.49 (0.008) | 0.54 (0.007) | 0.66 (0.007) | 0.67 (0.006) | 0.68 (0.007) | 0.73 (0.005) | 0.66 (0.007) | 0.76 (0.005) | 0.78 (0.005) | 0.81 (0.005) | 0.68 (0.002) |
| 3 years | 0.47 (0.008) | 0.53 (0.007) | 0.64 (0.007) | 0.63 (0.006) | 0.67 (0.007) | 0.71 (0.006) | 0.68 (0.007) | 0.72 (0.005) | 0.76 (0.006) | 0.79 (0.006) | 0.66 (0.002) |
| 4 years | 0.43 (0.008) | 0.49 (0.008) | 0.61 (0.007) | 0.62 (0.007) | 0.65 (0.007) | 0.68 (0.007) | 0.64 (0.007) | 0.70 (0.006) | 0.71 (0.007) | 0.75 (0.006) | 0.63 (0.002) |
| 5 years | 0.43 (0.008) | 0.50 (0.008) | 0.57 (0.008) | 0.58 (0.007) | 0.63 (0.007) | 0.67 (0.007) | 0.59 (0.007) | 0.68 (0.006) | 0.67 (0.008) | 0.73 (0.007) | 0.61 (0.002) |
| Total cost (SE)† | £8657 (£157) | £7715 (£81) | £7495 (£73) | £7081 (£63) | £7185 (£69) | £7567 (£82) | £7619 (£102) | £7128 (£61) | £7399 (£94) | £6917 (£67) | £7458 (£28) |
| QALYs with TKR (SE)† | 2.17 (0.029) | 2.48 (0.027) | 2.94 (0.024) | 2.99 (0.022) | 3.13 (0.025) | 3.30 (0.022) | 3.09 (0.025) | 3.40 (0.019) | 3.50 (0.020) | 3.67 (0.020) | 3.08 (0.025) |
| QALYs without TKR (SE)† | 0.15 (0.02) | 0.62 (0.022) | 0.94 (0.026) | 1.14 (0.026) | 1.63 (0.029) | 2.04 (0.026) | 2.39 (0.026) | 2.55 (0.021) | 2.78 (0.02) | 3.02 (0.02) | 1.75 (0.031) |
| QALY gain from TKR (SE)† | 2.02 (0.032) | 1.86 (0.031) | 2.00 (0.033) | 1.85 (0.031) | 1.51 (0.034) | 1.26 (0.030) | 0.69 (0.027) | 0.85 (0.023) | 0.73 (0.02) | 0.65 (0.02) | 1.33 (0.01) |
| ICER† | £4295 | £4153 | £3747 | £3836 | £4770 | £6007 | £10 971 | £8391 | £10 167 | £10 697 | £5623 |
↵* EQ-5D utility is measured on a scale from 1 (perfect health) to −0.594, where 0 is equivalent to death.
↵† Discounted at 3.5% per annum.
ICER, incremental cost-effectiveness ratio; KAT, Knee Arthroplasty Trial; OKS, Oxford Knee Score (new scoring system running from zero (severe problems on all functions) to 48 (no problems))41; QALY, quality-adjusted life year; SE, standard error around the mean; TKR, total knee replacement.