Table 5

Effect of duration of symptoms and time to surgery on outcomes.

PROM	Coeff	95% CI	P Value^a	P Value^b	P Value^c
VAS back
Preoperative	0.7	−0.4 to 1.8	0.196	0.090	0.163
6 wk	1.8	0.7–2.9	0.002	0.006	0.003
12 wk	2.7	1.7–3.8	<0.001	<0.001	<0.001
6 mo	2.8	1.7–3.9	<0.001	<0.001	<0.001
1 y	2.5	0.9–4.1	0.002	0.054	0.005
VAS leg
Preoperative	−0.5	−1.7 to 0.8	0.480	0.548	0.539
6 wk	1.5	0.3–2.7	0.012	0.032	0.041
12 wk	1.7	0.5–2.9	0.005	0.005	0.002
6 mo	1.8	0.6–2.9	0.003	0.001	0.006
1 y	2.1	0.3–4.0	0.021	0.032	0.145
ODI
Preoperative	9.4	3.2–15.7	0.003	0.001	0.002
6 wk	18.4	10.3–26.5	<0.001	<0.001	<0.001
12 wk	21.1	13.9–28.4	<0.001	<0.001	<0.001
6 mo	23.4	16.5–30.3	<0.001	<0.001	<0.001
1 y	14.6	2.5–26.7	0.019	0.009	0.018
SF-12 PCS
Preoperative	−5.6	−9.0 to –2.2	0.002	<0.001	0.002
6 wk	−6.7	−10.9 to –2.7	0.001	0.002	0.001
12 wk	−9.8	−14.3 to –5.2	<0.001	<0.001	<0.001
6 mo	−14.7	−20.0 to 9.3	<0.001	<0.001	<0.001
1 y	−12.2	−18.3 to –6.0	<0.001	0.001	0.001
PROMIS-PF
Preoperative	−4.0	−6.3 to –1.6	0.001	0.002	0.001
6 wk	−4.5	−7.7 to –1.2	0.007	0.009	0.010
12 wk	−5.0	−8.5 to –1.6	0.005	0.012	0.010
6 mo	−6.1	−9.9 to –2.2	0.002	0.001	0.004
1 y	−8.2	−13.4 to –2.9	0.003	0.011	0.009

Boldface indicates statistical significance.
aP value was calculated using simple linear regression to determine effect of workers’ compensation status and preoperative duration of symptoms.
bP value was calculated using multiple linear regression to determine effect of workers’ compensation while accounting for duration of preoperative symptoms.
cP values calculated using multiple linear regression to determine effect of workers’ compensation status while accounting for time to surgery.
ODI, Oswestry Disability Index; PROM, Patient-Reported Outcome Measures; PROMIS-PF, Patient-Reported Outcome Measurement Information System physical function; SF-12 PCS, 12-Item Short Form Physical Component Summary; VAS, visual analog scale; WC, workers’ compensation.