Table 3 EQ-5D utility values for different BMI groups (pre-surgery N = 1521, 12-month N = 1286)

normal: < 25

0.66 (0.49–0.83)

0.90 (0.31–1.00)

0.24 (0.21–0.27)

pre-obesity: 25–30

0.66 (0.55–0.77)

0.90 (0.79–1.00)

0.24 (0.22–0.26)

class I obesity: 30–35

0.61 (0.45–0.77)

0.89 (0.71–1.00)

0.28 (0.25–0.31)

class II obesity: 35–40

0.58 (0.11–1.00)

0.86 (0.12–1.00)

0.28 (0.23–0.33)

class III obesity: ≥ 40

0.54 (-0.09–1.00)

0.85 (-0.09–1.00)

0.30 (0.24–0.37)

Group

Time

Group-by-time interaction

F = 9.1; p < 0.001

F = 785.9; p < 0.001

F = 2.2; p = 0.066