Table 5: Adjusted* mean change in outcome from referral to immediately preoperatively for the 2 wait time groups

Outcome measure	Wait time; mean change in score (SE)†		Mean difference in change (95% CI)
Outcome measure	Shorter (≤ 12 mo)	Longer (> 12 mo)	Mean difference in change (95% CI)
SF-36 PC summary score	-0.8 (0.9)	-1.3 (0.9)	0.5 (-1.5 to 2.6)
SF-36 MC summary score	-0.9 (1.5)	-1.6 (1.6)	0.6 (-2.8 to 4.1)
ODI score	6.6 (1.5)	3.9 (1.6)	2.7 (-0.9 to 6.2)
ZCQ score	0.2 (0.1)	0.2 (0.1)	0.01 (-0.2 to 0.2)
Back pain score	0.7 (0.5)	0.6 (0.6)	0.1 (-1.0 to 1.2)
Leg pain score	0.4 (0.3)	0.2 (0.4)	0.3 (-0.4 to 1.0)

Note: CI = confidence interval, MC = mental component, ODI = Oswestry Disability Index, PC = physical component, SE = standard error, SF-36 = 36-Item Short-Form Health Survey, ZCQ = symptom severity scale of the Zurich Claudication Questionnaire.

*Adjusted for age, surgeon, duration of symptoms at consultation and surgery type.

†For SF-36 PC summary score and MC summary score, a negative change indicates deterioration. For ODI score, ZCQ score, back pain score and leg pain score, a positive change indicates deterioration.