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Table 3 QALY calculation – separated by preoperative WOMAC score

From: The impact of preoperative patient characteristics on the cost-effectiveness of total hip replacement: a cohort study

Visual analog scale (gold standard): VAS adjusted life years (VAS-AL)
WOMAC pre-operative N Mean EQ-5D VAS pre-operative SD Mean EQ-5D VAS post-operative SD Mean change EQ-5D VAS SD Life expectancy SD Mean costs in € SD Mean costs incl. potential revision SD VAS-AL SD VAS-AL disc. 3.5% Cost/VAS-AL in € Cost/VAS-AL disc. 3.5%
0-20 14 47.50 21.68 74.86 16.49 27.36 23.26 16.48 7.95 7,043 1,813 8,421 1,778 4.10 3.25 3.38 2,055 2,313
21-40 75 50.09 22.85 71.99 22.07 21.89 27.63 16.71 8.68 6,698 1,860 8,100 2,304 4.46 6.93 2.73 1,816 2,737
41-60 110 59.19 17.86 78.10 19.95 18.91 22.82 17.16 7.9 6,198 1,036 7,582 1,843 3.25 4.88 2.41 2,332 2,892
61-80 77 68.09 16.48 83.31 12.44 15.22 20.35 18.58 7.16 6,034 978 7,487 1,419 2.79 3.99 2.05 2,684 3,310
81-100 16 79.69 16.23 86.63 10.79 6.94 17.55 20.39 7.61 5,948 617 7,568 1,118 2.27 4.73 1.00 3,337 6,757
Sum 292 59.76 20.72 78.22 18.78 18.45 23.55 17.57 7.92 6,310 1,341 7,730 1,854 3.43 5.23 2.39 2,256 2,964
UK preference-weighted index as underlying value set (QALY)
WOMAC pre-operative N Mean EQ-5D utility score pre-operative SD Mean EQ-5D utility score post-operative SD Mean change EQ-5D utility score SD Life expectancy SD Mean costs in € SD Mean costs incl. potential revision SD QALY SD QALY disc. 3.5% Cost/QALY in € Cost/QALY disc. 3.5%
0-20 14 0.04 0.12 0.81 0.17 0.77 0.16 16.48 7.95 7,043 1,813 8,421 1,778 12.40 6.17 9.50 679 823
21-40 75 0.30 0.31 0.76 0.25 0.46 0.33 16.71 8.68 6,698 1,860 8,100 2,304 8.20 8.78 5.76 987 1,300
41-60 110 0.54 0.25 0.86 0.15 0.31 0.28 17.16 7.90 6,198 1,036 7,582 1,843 5.85 6.77 3.98 1,295 1,751
61-80 77 0.70 0.17 0.88 0.16 0.18 0.24 18.58 7.16 6,034 978 7,487 1,419 3.28 4.64 2.40 2,281 2,829
81-100 16 0.80 0.06 0.94 0.10 0.14 0.14 20.39 7.61 5,948 617 7,568 1,118 3.16 2.81 2.03 2,393 3,329
Sum 292 0.51 0.30 0.84 0.19 0.33 0.31 17.57 7.92 6,310 1,341 7,730 1,854 5.95 7.08 4.25 1,300 1,669
German experience-weighted index as underlying value set (EB-QALY)
WOMAC pre-operative N Mean EQ-5D utility score pre-operative SD Mean EQ-5D utility score post-operative SD Mean change EQ-5D utility score SD Life expectancy SD Mean costs in € SD Mean costs incl. potential revision SD EB-QALY SD EB-QALY disc. 3.5% Cost/EB-QALY in € Cost/EB-QALY disc. 3.5%
0-20 14 0.34 0.06 0.72 0.17 0.39 0.15 16.48 7.95 7,043 1,813 8,421 1,778 6.49 4.60 4.76 1,297 1,643
21-40 75 0.44 0.13 0.71 0.18 0.27 0.18 16.71 8.68 6,698 1,860 8,100 2,304 4.71 5.09 3.39 1,721 2,207
41-60 110 0.53 0.12 0.77 0.14 0.24 0.17 17.16 7.90 6,198 1,036 7,582 1,843 4.39 4.17 3.04 1,726 2,292
61-80 77 0.65 0.12 0.80 0.12 0.15 0.17 18.58 7.16 6,034 978 7,487 1,419 2.79 3.62 2.02 2,685 3,368
81-100 16 0.73 0.08 0.86 0.06 0.12 0.11 20.39 7.61 5,948 617 7,568 1,118 2.59 2.20 1.75 2,920 3,856
Sum 292 0.54 0.16 0.76 0.15 0.22 0.18 17.57 7.92 6,310 1,341 7,730 1,854 4.05 4.32 2.90 1,908 2,439